German Edition: DOI: 10.1002/ange.201506456Perovskite PhasesInternational Edition: DOI: 10.1002/anie.201506456

Giant Magnetoresistance in the Half-Metallic Double-PerovskiteFerrimagnet Mn2FeReO6Man-Rong Li, Maria Retuerto, Zheng Deng, Peter W. Stephens, Mark Croft, Qingzhen Huang,Hui Wu, Xiaoyu Deng, Gabriel Kotliar, Javier Snchez-Bentez, Joke Hadermann, David Walker,and Martha Greenblatt*

Abstract: The first transition-metal-only double perovskitecompound, Mn2+2Fe

3+Re5+O6, with 17 unpaired d electronsdisplays ferrimagnetic ordering up to 520 K and a giantpositive magnetoresistance of up to 220 % at 5 K and 8 T.These properties result from the ferrimagnetically coupled Feand Re sublattice and are affected by a two-to-one magnetic-structure transition of the Mn sublattice when a magnetic fieldis applied. Theoretical calculations indicate that the half-metallic state can be mainly attributed to the spin polarizationof the Fe and Re sites.

Perovskite oxides with unpaired d electrons present scien-tifically and practically interesting electronic and magneticproperties.[1–3] Recently, renewed interest has been focused onthe A2BB’O6 double perovskites (A = alkaline earth or rareearth metal or Pb; B/B’ = transition metals such as Fe/Mo andFe/Re) because of their colossal magnetoresistance (CMR)and half-metallic (HM) properties, which are potentiallyuseful for spintronic applications.[2, 4–6] The crystal structuresand physical properties of these materials can be effectivelymanipulated by controlling the size of the A site cations.[7]

Perovskites with unusually small A site cations are anemerging field for exotic properties,[8] especially whentransition-metal ions with unpaired d electrons are incorpo-rated into the A site for an improved performance.[9] Gen-erally, these materials can only be prepared at high pressureand temperature (HPT), and owing to their small tolerancefactors (t), the perovskite structures compete with corundum-related structures.[10–14] To the best of our knowledge, onlythree ABO3/A2BB’O6 type perovskites, namely MnVO3(Pnma, antiferromagnetic (AFM) metal)[9, 15] andMn2MSbO6 (M = Fe and Cr),

[16, 17] have been prepared with

transition-metal ions at both the A and B sites. The perovskitepolymorphs Mn2+2M

3+Sb5+O6 (P21/n) can be prepared at 5(M = Fe) and 8 GPa (M = Cr) with M3+ and Sb5+ ordered atthe B and B’ sites. Although high-spin (HS) d5 Mn2+ and Fe3+

and d3 Cr3+ ions occupy the A and B sites in Mn2MSbO6, theirproperties are not so remarkable (AFM insulators with TN 60 and 55 K for M = Fe and Cr, respectively), likely becauseof the non-magnetic Sb5+ ion at the B’ site. Therefore, theincorporation of transition-metal ions at all of the cation sitesin A2BB’O6 was anticipated to result in unusual properties.Herein, we report the first transition-metal-ion-only doubleperovskite oxide Mn2FeReO6, which was synthesized by anHPT method. The crystal and magnetic structures as well asthe magnetotransport properties were experimentally andtheoretically investigated in detail.

Polycrystalline Mn2FeReO6 was prepared at 1623 K under5 GPa. Energy-dispersive X-ray spectroscopy gave a compo-sition of Mn1.98(10)Fe0.98(7)Re1.04(16)Ox, which is in good agree-ment with the nominal composition. The room temperature(RT) powder X-ray diffraction (PXD) patterns ofMn2FeReO6 indicate a pure phase with a monoclinic ororthorhombic cell (Supporting Information, Figure S1 a), butit is difficult to determine the space group (SG) owing to thesmall deviation of the monoclinic angle from 9088. This as-made phase was stable up to 850 K upon heating at ambientpressure, at which point it decomposed (Figure S1b). Sub-sequent electron diffraction experiments confirmed the celldimensions (Figure S2) and suggested a monoclinicP21/n (No. 14), or orthorhombic Pn type [Pnm21 or Pn21m(No. 31) or Pnmm (No. 59)] SG. Finally, the crystal structurewas conclusively determined to be monoclinic P21/n by high-resolution synchrotron PXD (SPXD) data refinements

[*] Dr. M. R. Li, Dr. M. Retuerto, Z. Deng, Prof. M. GreenblattDepartment of Chemistry and Chemical BiologyRutgers, The State University of New Jersey610 Taylor Road, Piscataway, NJ 08854 (USA)E-mail: martha@rutchem.rutgers.edu

Dr. M. RetuertoNiels Bohr Institute, University of Copenhagen2100 Copenhagen (Denmark)

Dr. P. W. StephensDepartment of Physics & AstronomyState University of New YorkStony Brook, NY 11794 (USA)

Dr. M. Croft, X. Deng, G. KotliarDepartment of Physics & AstronomyRutgers, The State University of New Jersey136 Frelinghuysen Road, Piscataway, NJ 08854 (USA)

Dr. Q. Huang, H. WuCenter for Neutron ResearchNational Institute of Standards and Technology (NIST)Gaithersburg, MD 20899-6102 (USA)

Dr. J. Snchez-BentezDepartamento de Qumica Fsica I, Facultad de Ciencias QumicasUniversidad Complutense de Madrid28040 Madrid (Spain)

Dr. J. HadermannEMAT, University of AntwerpGroenenborgerlaan 171, 2020 Antwerp (Belgium)

Dr. D. WalkerLamont-Doherty Earth Observatory, Columbia University61 Route 9W, Palisades, NY 10964 (USA)

Supporting information for this article is available on the WWWunder http://dx.doi.org/10.1002/anie.201506456.

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(Figure 1; a = 5.20098(2), b = 5.36399(2), c = 7.58904(3) è,b = 89.95(1)88, V = 211.719(1) è3, Rp/Rwp = 5.50/7.08%, c

2 =

1.65). Approximately 5(1)% of Fe and Re anti-site disorderwas observed, giving a compositional formula ofMn2(Fe0.95(1)Re0.05(1))(Re0.95(1)Fe0.05(1))O6. The refined struc-tural parameters and agreement factors are listed inTable S1, and selected interatomic distances and bondangles are given in Table S2. Mn2FeReO6 crystallizes ina highly distorted double-perovskite structure, where the Mncations are coordinated by eight oxygen atoms, and corner-sharing FeO6 and ReO6 octahedra are rock-salt-ordered overthe B and B’ sites (Figure 1, inset). It is isostructural withCa2FeReO6

[7] and Mn2FeSbO6,[18] and consistent with the

t-dependent structural evolution law for A2FeReO6 (A =alkali earth) complexes shown in Figure S3. The size of theMn2+ ions at the A positions is extremely small for a per-ovskite and forces the FeO6 and ReO6 octahedra to tilt inorder to optimize the Mn¢O distances. The tilting angle wasestimated using the parameter F = (18088¢q)/2 where q is theaverage angle of Fe1/Re1-O-Fe2/Re2. In Mn2FeReO6, thisangle is 140.6388 (Table S2), and therefore F = 19.788, whichindicates a significantly higher distortion than in otherdistorted perovskites, such as Ca2CrSbO6, where the A cationis bigger and F = 13.588.[19] The Mn¢O distances with eightfoldcoordination (2.379(10) è at room temperature; Table S2)are also smaller than other A¢O distances in distorted doubleperovskites, such as Ca2FeReO6 (Ca¢O = 2.499(3) è).[20]Bond valence sum (BVS, Table S2) calculations[21] suggestedformal oxidation states of Mn2+2Fe

3+Re5+O6, which wasconfirmed by X-ray absorption near-edge spectroscopy(XANES; Figure S4–S6).

Temperature-dependent magnetic susceptibil-ity [c(T)] measurements were performed between5 and 600 K (Figure 2 a). In the low-temperatureregime (5–400 K; see Figure 2a, i), the measure-ments were conducted by both zero field cooling(ZFC) and field cooling (FC). The ZFC and FCcurves diverge below 400 K owing to the competi-tion between different magnetic interactions, asmight be expected for a system with so manymagnetic ions. A high ferromagnetic TC of approx-imately 520 K was observed. Above TC, the recip-rocal susceptibility slightly deviated from linearbehavior with a parabolic shape, which is alsoa typical ferromagnetic behavior. A regular Curie–Weiss (CW) law was adopted for a good fit in therange of 530–600 K (Figure 2a, ii). The paramag-netic temperature (q = 502 K) is close to the TCobserved, which indicates that ferro- or ferrimag-netic interactions are predominant. The paramag-netic effective moment (meff = 4.4 mB/f.u.; f.u. = for-mula unit) is much smaller than the expected value(10.6 mB/f.u.). The large difference between theobserved and expected meff values may be attrib-uted to possible short-range order above TC, whichaffects the correct evaluation of c(T), or to spin–orbit coupling, which has been reported to have aneffect on meff for Re-based perovskites.

[22, 23]

The hysteresis loops indicate clear ferromagnetic behav-ior (Figure 2b). At 5 K, the saturation magnetization (ms) of4.9 mB/f.u. indicates ferrimagnetic (FiM) ordering of thecations, as it is much lower than the theoretical sum of thespin-only moments (17 mB/f.u.). Unlike for the A2FeMoO6family, where the large Fe-O-Mo bond angle deviation from18088 for smaller A cations reduces the dpd p coupling anddecreases TC, the Re analogues show the highest TC for thesmaller A cations, which was attributed to the strong spin–orbit coupling of the 5d transition metals,[24] giving a TC valueof 520 K for Mn2FeReO6, which is comparable with that ofCa2FeReO6 (ca. 530 K).

[7]

Interestingly, Mn2FeReO6 is more insulating than otherA2FeReO6 (A = alkali earth or Pb) phases, where theresistivity (1) varies between 0.05 and 1 Wcm at RT,[7, 25]

considering that Mn2FeReO6 has a greater number ofunpaired d electrons. Figure 3 shows the temperature depend-ence of the 1 value of Mn2FeReO6 at zero field and 8 T. Theresistivity values are almost identical above 150 K at 0 and8 T, with 1 = 4.98 (0 T) and 4.97 (8 T) Wcm at RT, indicatingthe absence of magnetoresistance (MR) at higher temper-atures. The 1 value increases slowly down to 50 K, and below50 K, the resistivity increases steeply with decreasing temper-ature. The small anomaly around 50 K is probably due tomagnetoelastic coupling, which is also observed in other Reperovskites (Ca2FeReO6)

[7] and has been reported to berelated to Re spin–orbit coupling that couples the magneticmoment with the lattice, as also supported by the latticeparameter evolution (Figure S7). At 5 K, the resistivity valuesincrease to 122.58 and 396.32 Wcm at 0 and 8 T, respectively,which corresponds to a positive MR of approximately 220 %.The isothermal MR ratio between ¢8 and 8 T at 5 K, with

Figure 1. Rietveld refinement of the SPXD data for Mn2FeReO6 in the monoclinicP21/n structure at RT. Asterisks indicate peaks from diamond diluent (internalstandard) accounting for 90% of the sample by weight. Tick marks indicate thepositions of allowed perovskite-phase peaks. The left inset shows the monoclinicsplitting of the (204) reflection. The right inset shows the crystal structure viewedalong [110] direction. Mn ions are shown as large spheres, O ions as small spheres,and the FeO6 and ReO6 octahedra are light and dark gray, respectively.

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a slim butterfly-like shape, is shown in the inset in Figure 3.Unlike other A2FeMO6 (M = Mo and Re) materials with

a negative MR ratio of approximately ¢15 %, the MR ofMn2FeReO6 is positive and much larger.

Powder neutron diffraction (PND) data, collected withand without an applied magnetic field at different temper-atures, were obtained to determine the magnetic structuresand to better understand the giant positive MR inMn2FeReO6 (Figure S8 and Tables S3 and S4). The magneticstructures at low temperature (4 and 70 K) and 0 T have to beexplained in terms of two different AFM structures: one forthe Mn cations and another one for the FiM arrangement ofthe Fe and Re moments. At 4 K and 0 T, the Mn moments arealigned antiferromagnetically along the x and z directions(mx = 2.05(11) mB, mz = 1.3(2) mB), and the y component isequal to zero in one magnetic structure (Figure 4a, left),

whereas the other magnetic structure (Figure 4a, middle) hasx and z components equal to zero, and only the y AFMcomponent deviates from zero (Mn my =¢2.91 mB). There-fore, the magnetic structure of Mn is represented by twodifferent sublattices with all of the components coupledantiferromagnetically, and cannot be explained with onesingle magnetic structure because this would correspond toa forbidden solution for its monoclinic space group. In thecase of Fe and Re, the Fe and Re moments are mx = mz =3.19(8) mB and mx = mz =¢0.143(3) mB, respectively, and thecomponents along the y axis are again zero; the Fe and Respins are antiparallel and form a net FiM structure (Figure 4a,right), which can be defined as a P21/m magnetic space group.The coexistence of two different Mn AFM structures and theFiM Fe/Re magnetic structure can account for the highresistivity of Mn2FeReO6 compared to similar phases withnon-transition-metal ions at the A sites.

The magnetic structure at 70 K and H = 0 T is the same asthat at 4 K and H = 0 T, but with smaller magnetic moments(Table S3). At 250 or 300 K and 0 T, the Fe and Re momentscorrespond to the same FiM structure as at 4 K and H = 0 T,but are smaller, while the Mn cations are no longer magneti-cally ordered (Table S3 and Figure 4b). To the best of ourknowledge, only Sr2CoOsO6 has been established to feature

Figure 2. a) The c(T) curves up to 600 K show the magnetic transitiontemperature (TC) of 520 K. i) ZFC and FC data up to 400 K. ii) Theinverse susceptibility (c¢1) versus temperature curve nicely fits to theCW model over the paramagnetic region. b) Isothermal magnetizationcurves at 5, 75, and 300 K between ¢5 and 5 T. Inset: Enlarged areabetween ¢0.6 and 0.6 T.

Figure 3. Temperature-dependent resistivity of Mn2FeReO6 at zero fieldand 8 T. Inset: The isothermal MR ratio between ¢8 and 8 T at 5 K,with the maximum positive MR ratio of approximately 220% at 8 T.

Figure 4. Magnetic structures of Mn2FeReO6 a) at 4 K and 0 T with twoAFM-coupled Mn sublattices and FiM spin alignment of the Fe/Relattice, b) at 250 K and 0 T with FiM ordering of Fe and Re, c) at 4 Kand 7 T with an AFM-coupled Mn lattice and a FiM Fe and Rearrangement, and d) at 250 K and 7 T with a FiM Fe and Re lattice.

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two interpenetrating magnetic sublattices with clearly differ-ent and independent ordering magnetic transitions among thedouble perovskites.[26] As the Mn sublattice is no longermagnetically ordered at high temperature, it cannot affect theFe and Re magnetic sublattice, and the resistance of thesample decreases compared to that at 4 K (Figure 4a). At 7 Tand 4 K, the simultaneous presence of two different magneticsublattices that defined the Mn magnetic structure at H = 0 Tis no longer valid. The second AFM Mn structure (Figure 4a,middle), together with the FiM sublattice of the Fe and Recations, can be used to explain the data (Figure S8c): Theapplied magnetic field (7 T) brings about a transition thatsimplifies the magnetic structure. The magnetic moments ofMn are now AFM-coupled and oriented along the y axis(my =¢2.93(5) mB), as the components along the x andz directions become zero (Figure 4c and Table S4). The FiMFe/Re sublattice gives a net magnetic moment of 5.0 mB, whichis similar to the saturation magnetization (4.9 mB) at 5 K and5 T (see Figure 2b). We propose that this magnetic structureat 4 K and 7 T hinders the half-metallicity of sublattice Bmore than the combination of magnetic structures found at0 T, which could explain the incremental change in theresistivity when a magnetic field is applied. At 250 K and 7 T,the magnetic structure (Figure 4d and Table S4) is similar tothat at 250 K and 0 T (Figure 4b). These magnetic-structureevolutions are also reflected by the PND patterns in Fig-ure S9. When an external magnetic field is applied, theorientation of the spin and orbital moments of Re could bemodified in a way that hinders the half-metallicity andincreases the global resistivity of the material. Other Redouble perovskites, Ba2MnReO6, and Ca2FeReO6 have beenreported to present positive MR,[27, 28] but with much smallervalues.

First-principle calculations based on density functionaltheory (DFT) can stabilize a collinear magnetic structure ofMn2FeReO6, which correctly captures the AFM and FiMcoupling of the Mn and Fe/Re sublattices, respectively. Thecorresponding density of states (DOS) and the electronicband structure are shown in Figures 5 and S10. Both the Mnand Fe sites are nearly fully polarized by a large exchangesplitting between the spin majority and minority components,while the Re site is weakly polarized with a much smaller

exchange splitting. The scenario is in agreement with thePND measurements, where large moments were observed forthe Mn and Fe sites and a much smaller moment for theRe site. Interestingly, the DOS exhibits a significant insulatinggap (ca. 1.0 eV) in the spin majority component anda relatively high density of states in the spin minoritycomponent at the Fermi level; thus the pronounced HMbehavior is mainly due to the Re and Fe sites. Therefore, it islikely that the half-metallicity of the Fe/Re sublattice isaffected by the complicated magnetic structure of theMn sites in a way that an external magnetic field wouldmodify the electronic structure to produce the observed giantpositive MR. It is also possible that the spin–orbit coupling ofthe Re moments has an effect on the positive MR, but thispoint needs further clarification.

In conclusion, the first transition-metal-only doubleperovskite compound, Mn2FeReO6, has been prepared athigh pressure and temperature, and was experimentally andtheoretically established to be a half-metallic ferrimagnet(TC = 520 K) above room temperature with giant positivemagnetoresistance (ca. 220%). These findings set a record forthe number of unpaired d electrons (17) in a double per-ovskite oxide and will encourage further searches for newmultifunctional materials.

Experimental SectionExperimental details, electron-diffraction and crystal-structure data,XANES, detailed powder neutron diffraction data analysis, low-temperature lattice parameter evolution, and theoretical calculationsare presented in the Supporting Information. Further details on thecrystal structure investigation may be obtained from the Fachinfor-mationszentrum Karlsruhe, 76344 Eggenstein-Leopoldshafen, Ger-many (fax: (+ 49)7247-808-666; e-mail: crysdata@fiz-karlsruhe.de),quoting the depository numbers CSD429762 to 429768.

Acknowledgements

This work was supported by NSF-DMR-0966829 and ARO-434603 (DOD-VV911NF-12-1-0172) grants. X.D. and G.K.are supported by the NSF-DMREF project DMR-1435918.J.S.-B. is supported by the Spanish projects MAT2013-41099-R and RyC-2010-06276. M.R. is supported by the DanishResearch Councils for Independent Research (12-125226).Use of the NSLS, Brookhaven National Laboratory wassupported by the DOE BES (DE-AC02-98CH10886). Wewould like to thank J. Hanley at LDEO, Columbia Universityfor making the high-pressure assemblies, and Dr. TapatiSarkar at Uppsala University for the original magnetismcheck.

Keywords: density functional calculations ·giant magnetoresistance · half-metallicity · magnetic properties ·perovskite phases

How to cite: Angew. Chem. Int. Ed. 2015, 54, 12069–12073Angew. Chem. 2015, 127, 12237–12241

Figure 5. The computed DOS of Mn2FeReO6 and its projections ontothe d orbitals of different sites. Positive (negative) values correspondsto spin majority (minority) components.

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Received: July 13, 2015Published online: July 31, 2015

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Supporting Information

Giant Magnetoresistance in the Half-Metallic Double-PerovskiteFerrimagnet Mn2FeReO6Man-Rong Li, Maria Retuerto, Zheng Deng, Peter W. Stephens, Mark Croft, Qingzhen Huang,Hui Wu, Xiaoyu Deng, Gabriel Kotliar, Javier S�nchez-Ben�tez, Joke Hadermann, David Walker,and Martha Greenblatt*

anie_201506456_sm_miscellaneous_information.pdf

1

Supplementary Text

1. Experimental Details

1.1 Synthesis, Powder X-ray Diffraction, and Phase Stability

Polycrystalline Mn2FeReO6 was prepared from a stoichiometric mixture of MnO

(99.99%, Alfa Aesar), Fe2O3 (99.998%, Alfa Aesar), Re (99.99%, Alfa Aesar), and ReO3

(99.99%, Alfa Aesar) at 1623 K for 1 h under 5 GPa in a multianvil press and then quenched

to room temperature (RT) by turning off the voltage supply of the resistance furnace as

reported in our previous work.[1-4] The pressure was maintained during the temperature

quenching and then decompressed slowly in 8 - 12 h. Original laboratory powder X-ray

diffraction (PXD, Figure S1a) patterns were collected in a Bruker D8 Advance diffractometer

(Cu Kα, λ = 1.5418 Å), which indicates monoclinic (a = 5.20(1), b = 7.59(1), c = 5.36(1) Å, β

≈ 90.01(1)º), or orthorhombic (a = 7.59(1), b = 5.20(1), c = 5.36(1) Å) cell.

Phase stability of the as-made Mn2FeReO6 was examined by thermal gravimetric

analysis (TGA) and differential scanning calorimetry (DSC) in a SDT Q600 TA Instrument.

The sample was examined between 450 and 1000 K (temperature interval of 50 K) in Ar flow

with heating and cooling rates of 5 K/min, and isothermal time of 30 min at each temperature.

No phase transition was observed from the TGA-DSC curves until it was decomposed above

850 K. Room-temperature PXD data were also collected to examine the phase after each

TGA-DSC cycle on the above Bruker D8 Advance Diffractometer (Figure S1b).

1.2 Electron Diffraction

The composition of Mn2FeReO6 was verified with scanning electron microscope

(JEOL JSM5510) based energy-dispersive X-ray (SEM-EDX) spectroscopy analysis on 50

different crystallites. Selected area electron diffraction (SAED) patterns were obtained on a

2

Philips CM20 transmission electron microscope to verify the crystal structure. High-

resolution transmission electron microscopy (HR-TEM) was obtained with a Tecnai G2

transmission electron microscope.

1.3 Powder Synchrotron X-ray Diffraction

RT synchrotron powder X-ray diffraction (SPXD) data of Mn2FeReO6 were recorded

on beam line X-16C (λ = 0.70018 Å) at the Brookhaven National Synchrotron Light Source

(NSLS) in US. In situ variable temperature SPXD measurements were also carried out

between 10 and 80 K with step of 10 K on beam line X-16C (λ = 0.69956 Å). Diamond

powder was used as an internal standard. Diffraction data analysis and Rietveld refinements[5]

were performed with the TOPAS software package[6] and EXPGUI interface of GSAS

program.[7]

1.4 Powder Neutron Diffraction

Powder neutron diffraction (PND) data were collected on about 1 g of polycrystalline

Mn2FeReO6 pellet at the NIST Center for Neutron Research (NCNR) with the BT-1 high-

resolution neutron powder diffractometer (λ = 2.0775 Å). The sample was first measured at

300 and 250 K for 7 h without magnetic field, and then at 70 and 4 K for 9 h also without

field. Subsequently, the data were collected at 4 and 250 K under a magnetic field of 7 T. The

Fullprof program was used to refine and solve the PND crystallographic and magnetic

structures.[8]

1.5 X-ray Absorption Near Edge Spectroscopy

Mn-K, Fe-K and Re-L3 X-ray absorption near edge spectroscopy (XANES) data were

collected in both the transmission and fluorescence mode with simultaneous standards. All of

the spectra were fit to linear pre- and post-edge backgrounds and normalized to unity

3

absorption edge step across the edge.[4, 9-16] All of the XANES was performed on beam line

X-19A at the Brookhaven NSLS with a Si-111 double crystal monochromator.

1.6 Mangetism and Magnetotransport

Magnetization measurements were carried out with a commercial Quantum Design

superconducting quantum interference device (SQUID) magnetometer. The magnetic

susceptibility () was measured in zero field cooled (ZFC) and field cooled (FC) conditions

under a 0.1 T applied magnetic field (H), for temperatures ranging from 5 to 400 K. We

performed FC measurements (at 0.01 T) up to 600 K to determine the magnetic transition

temperature. Isothermal magnetization curves were obtained at T = 5, 75 and 300 K under an

applied magnetic field varying from -5 – to 5 T. The magnetotransport properties were

measured on a pellet sample with the standard four-probe technique in a physical property

measurement system (PPMS) from Quantum Design at 0 and 8 T, respectively. To avoid the

Joule heating effect, measurements were carried out with less than 0.5 μA current. The

magnetoresistance is defined as)0(

)0()(100)(

R

RHRHMR

, where R(H) is the resistivity at H and

R(0) is the resistivity without H.

1.7 Theoretical Calculations

First principles calculations of Mn2FeReO6 based on density functional theory are

performed using the full-potential linearized augmented plane wave method, as implemented

in the WIEN2k package.[17] The Perdew-Burke-Ernzerhof generalized gradient

approximation of exchange-correlation functions was adopted.[18] The muffin tin radii are

chosen to be the 2.12, 2.04, 1.96, 1.68 Bohr radius for Mn, Fe, Re, O respectively, and the

cut-off parameter 𝑅𝑚𝑡𝐾𝑚𝑎𝑥 is 7.0. The experimental crystallographic structure given in Table

S1 is used.

4

2. Electron Diffraction Analysis

Tilt series were taken with a total of around 30 different zone axis patterns, divided

over 8 different series. The results below are for the crystallites that do fit the given cell

parameters (disregarding the deviation from 90° for beta). Representative ED patterns of the

main zones are given in Figure. S2. From these patterns, the following reflection conditions

could be derived: hkl: no conditions, 0kl: k + l = 2n, h0l: no conditions, hk0: no conditions,

h00: h = 2n, 0k0: k = 2n, 00l: l = 2n. The reflection condition h00: h = 2n is shown on the top

right pattern, where a tilt out of the zone axis has been made to eliminate double diffraction

paths, which leads (right side of the pattern) to the disappearance of the h00 reflections with

odd h. Since any deviation from 90° between the a*, b* and c* axes is too small to quantify

from TEM, both monoclinic and orthorhombic possibilities would be in agreement with the

ED patterns. In the monoclinic case, these reflection conditions would lead to P21/n11 (No.

14). For the orthorhombic case, to the extinction symbol Pn-- (SG Pnm21, Pn21m, Pnmm), in

which case however h00: h = 2n is not a requirement. The h00 reflections could be present,

but too weak to discern. If this is the case, this would also allow Pn instead of P21/n for the

monoclinic case.

3. Crystal Structure of Mn2FeReO6 and Lattice Evolution in A2FeReO6

In Mn2FeReO6 structure, the average and bond distances (2.022(10)

and 1.961(9) Å, respectively) are comparable with the values in other A2FeReO6 phases

(1.957 Å ≤ ≤ 2.067 Å, 1.941 ≤ ≤ 1.997), being the longest ones among the

monoclinic phases (Figure S3). The average bond distance in Mn2FeReO6

(2.379(10) Å) is similar to corresponding values in Mn2FeSbO6 (2.397(8) Å),[19] and MnVO3

(2.344(9) Å). However, the Fe-O-Re angle (~ 140º) in Mn2FeReO6 is much smaller than that

5

of Ca2FeReO6 (~ 156º) due to the high structural distortion, because of the very small size of

VIIIMn2+ (0.96 Å) for the A position of the perovskite.

Considering the crystal structure evolution in A2FeReO6, the crystal structure of

Mn2FeReO6 is in line with those of other compounds with A2 = Ba2, BaSr, Sr2, SrCa,

Sr0.5Ca1.5, Ca2, and Pb2,[20-22] which undergo two phase transitions when the A-site cation size

becomes smaller from Ba2+ to Mn2+: cubic (Fm-3m) Ba2FeReO6 and BaSrFeReO6 to

tetragonal (I4/m) Pb2FeReO6 and Sr2FeReO6, and then to monoclinic (P21/n) SrCaFeReO6,

Sr0.5Ca1.5FeReO6, Ca2FeReO6, and Mn2FeReO6. These structural phase transitions can be

better understood considering the variations of average A-site ionic radius and tolerance

factor (t) as highlighted by the two vertical dashed lines in Figure. S3. Note that here the

average ionic radii at eight coordination environment () are used to calculate the t

values for comparison since the ionic radius of Mn2+ is unknown for 12-fold coordination.[23]

Changes of the average and bond lengths in A2FeReO6 is more complicated

and related to not only the A-site cation size, but also other factors, such as the electron

configuration of the A-site cations and charge distribution and ordering degree over the B-site

Fe and B'-site Re.[24-25] For example, Pb2+ has comparable size with Sr2+ but the shortest and longest in the series as shown in Figures S3a and b, probably due to its 6s2

lone pair electrons of Pb2+. Moreover, Pb2FeReO6 can be prepared with different Fe/Re

disordering degree by controlling the cooling rate, giving around 10% and 30% Fe/Re

disordering in the slowly cooled (denoted as Pb2(S) in Figure. S3) and quenched (denoted as

Pb2(Q) in Figure. S3) samples, accordingly, different (1.973 and 1.957 Å for Pb2(S)

and Pb2(Q), respectively) and (1.997 and 1.967 Å for Pb2(S) and Pb2(Q)) are

observed.[22] The large Ba2+ is reported to strongly affect the charge distribution on the Fe-O-

Re sublattice, leading to mixed Fe(3-δ)+ valence and the longest of 2.067 Å is

observed in Ba2FeReO6.[20] Although the and values fluctuate and are

6

affected by many factors, their variation tendency is clear (except for Pb2FeReO6)

diminishing with the decrease of t and in the Fm-3m and I4/m phases, but increasing

with the decrease of t and in the P21/n phases.

Compared with the bond lengths, the unit cell volume (V) evolution is simpler (Unit cell

volumes of the tetragonal and monoclinic phases are doubled for overall comparison given

the small distortion from the cubic phase). V decreases linearly with the decreasing of t and

but following different slopes in the cubic, tetragonal and monoclinic phase space,

respectively as illustrated in Figure. S3c. It is interesting that all the anomalies in the

and linear variation trend and with V evolution, appear at the tetragonal and

monoclinic phase boundary, indicating systematic coupling between the crystal lattice and

metal-oxygen bond. Thus, further studies are necessary to understand the chemical and

crystallographic properties of A2FeReO6.

4. XANES

4.1 Mn-K edge

The main edge features at 3-d transition metal K edges are dominated by 1s to 4p

transition peak-features, along with a step-continuum-onset-feature. The 4p features can be

complicated by splittings into multiple features by the local atomic coordination/bonding and

by admixed 3d configurations. Nevertheless these features manifest a chemical shift to higher

energy with increasing valence, allowing the use of the K edge to chronicle the evolution of

the transition metal valence state in compounds.[9-14] In Figure S4a the Mn-K near edge of

Mn2FeReO6 is plotted along with those standard Mn compounds with varying valence.[9-10]

Comparing the energy shifts in strongly rising portion of the main edge spectra in Figure S4a,

the low energy of the Mn2FeReO6 chemical shift indicates a Mn2+ valence in this material.

7

The Mn-K pre-edge features of the same spectra are shown in Figure.S4b. This pre-

edge region is related to transitions into 3d final states either via quarapole or dipole (by d/p-

hybridization) transitions. The spectral structure and chemical shift of the pre-edge features

also can be used to follow valence changes between compounds. [9-14] The low energy of the

Mn2FeReO6 pre-edge features further supports the Mn2+ valence in this material. It is

interesting to note in Figure S4b that the standard spectra all have octahedral Mn-O

coordination. By contrast the Mn-O coordination in Mn2FeReO6 is a highly distorted version

of the A-site in the perovskite structure which would have an inverted ligand field structure.

Indeed, in the monoclinic structure of Mn2FeReO6, the MnO8, A-site coordination is not only

reduced from the 12 coordinate perovskite value, but is further distorted with four short and

four long bonds. The pre-edge feature for the Mn2FeReO6 is enhanced in magnitude

consistent with d/p hybridization allowed by the non-centro-symmetric highly distorted local

coordination.

4.2 Fe-K edge

In Figure.S5a Fe-K edges are compared to a series of standard compounds. As in the

Mn case above, the nominal proximity of the main edge rise for various formal valence states

is indicated.[4, 11-15] The main edge chemical shift results, in Figure 2a, support a basically

Fe3+ state assignment in the Mn2FeReO6 compound.

The Fe-K pre-edge regions for the same compounds are shown in Figure. S5b. All of

the Fe-K pre-edges manifest a dual, a-b feature structure. Although the intensities of the a- vs.

b-features can vary substantially with local distortions and d-configuration, they manifest a

chemical shift to higher energy with increasing valence (as noted for Mn above). The energy

and structure of the Mn2FeReO6 pre-edge spectrum is, again, consistent with the Fe3+ state in

8

this compound.[4, 11-15] It should however be noted that that the intensity of the Mn2FeReO6

pre-edge, and its b-feature in particular, is enhanced.

4.3 Re-L3 edge

The L3 edges of transition metals are dominated by very intense ‘‘white line’’ (WL)

features due to dipole transitions into final d states. Octahedral O-ligand coordination

imposes a ligand field (LF), splitting of the d-states, into lower energy, 6X degenerate, t2g and

higher energy, 4X degenerate, eg multiplets. This LF splitting can be clearly observed at the

Re–L3 edges as splitting of the WL feature into A (t2g related) and B (eg related) features as

illustrated by the Re-L3 edge for the d0, Re7+ compound SrFe3/4Re1/4O6 in Figure S6a.

[4, 11-15]

In general increases in the 5d-electron count (decreases in the 5d-hole count) lead to a

reduction in the relative A-feature intensity, although matrix element and bonding/band

structure effects can lead to variations in the A-B feature splittings and intensities. In Figure

S6a the general trend of decreasing relative A-intensity with increasing valence can be seen.

Another indicator of the Re d-configuration/valence state is the chemical shift of the WL

feature. Referring to Figure S6a one should note the systematic chemical shift upward in WL-

feature centrum energy in the sequence of ~d3-Re4+, ~d2-Re5+, ~d1-Re6+, and ~d0-Re7+ spectra.

Figure.S6b compares the Re-L3 edge for Mn2FeReO6 to those of selected ~d1-Re6+

and ~d2-Re5+ standards with corner sharing octahedra from the previous figure. The A-B peak

structure of the Mn2FeReO6 spectrum is close to that of the Ca2CrReO6 ~d2-Re5+ standard.

The chemical shift of the Mn2FeReO6 spectrum is clearly shifted down in energy into the

~d2-Re5+ range. Hence the Re-L3 edge results for Mn2FeReO6 are consistent with a basically

~d2-Re5+ assignment.

9

5. Lattice Parameter Evolution at Low Temperature

Figure S7 shows the temperature dependent lattice parameter variation in Mn2FeReO6

between 10-80 K. Above 50 K, the lattice parameters follow one linearity, while below 50 K,

they deviate to another linearity with a smaller slope. This lattice parameter evolution

indicates possible frustration or magnetostriction around 50 K, which could cause giant

positive MR.

6. Powder Neutron Diffraction Analysis

PND data were collected with and without applied magnetic field at different

temperatures, in order to determine the magnetic structures and to establish if the large 220%

positive MR is related to changes in the magnetic structure. Without an applied magnetic

field PND data were collected at 4, 70, 250 and 300 K, and with an applied magnetic field of

7 T at 4 and 250 K for comparison. The Basireps program (embedded in FullProf Suite)[8]

was employed to obtain the possible Irreducible Representations for P21/n space group and

the propagation vector k = 0 (which was also found with FullProf). There are four possible

irreducible representations for the Mn cations (all in the same (x, y, z) position of P21/n).

When the symmetry of the structure is reduced to P-1, to define the magnetic structure, the

Mn position splits into four different sites: Mn1 (x, y, z), Mn2 (-x + 1/2, y + 1/2, -z + 1/2),

Mn3 (-x, -y, -z) and Mn4 (x + 1/2, -y + 1/2, z + 1/2). The possible irreducible representations

to explain the magnetic structure are listed below: solution 1 (Gx, Fy, Gz) with (m1x -m2x m3x -

m4x, m1y m2y m3y m4y, m1z -m2z m3z -m4z); solution 2 (Ax, Cy, Az) with (m1x -m2x -m3x m4x, m1y

m2y -m3y -m4y, m1z -m2z -m3z m4z); solution 3 (Fx, Gy, Fz) with (m1x m2x m3x m4x, m1y -m2y m3y -

m4y, m1z m2z m3z m4z); and solution 4 (Cx, Ay, Cz) with (m1x m2x -m3x -m4x, m1y -m2y -m3y m4y,

m1z m2z -m3z -m4z). And for Fe in (0 ½ 0) and (½ 0 ½) and Re cations in (0 ½ 0) and (½ 0 ½)

10

there are two possible representations for each: Solution 1 (Gx, Fy, Gz) with (m1x -m2x, m1y

m2y, m1z -m2z); and solution 2 (Fx, Gy, Fz) with (m1x m2x, m1y -m2y, m1z m2z).

For the data at 4 K and 0 T none of the possible simple combinations give a result that

can explain the data. Thus the magnetic structure has to be explained with two different

magnetic structures for Mn cations, (Gx, Fy, Gz) and (Fx, Gy, Fz) solutions. In (Gx, Fy, Gz) the

Mn moments are aligned antiferromagnetically along the x and z directions (mx = 2.05(11) μB,

mz = 1.3(2) μB) and the y component equal to 0, while the second magnetic structure (Fx, Gy,

Fz) has x and z components equal to zero and only the y antiferromagnetic component is

different to zero (Mn my = -2.91 μB). Thus the magnetic structure of Mn can be seen as two

different sublattices with all the components AFM coupled (see Figure 4a in the main text).

In the case of Fe and Re the magnetic structure can be explain with (Gx, Fy, Gz) solution

where Fe moments are mx = mz = 3.19(8) μB and Re mx = m z= -0.143(3) μB and the

component along y is zero. Fe and Re spins are antiparallel, forming a net ferrimagnetic

structure (that can be defined with P21/m magnetic space group). The coexistence of both Mn

antiferromagnetic sublattices and the ferrimagnetic Fe-Re magnetic sublattice can account for

the high resistivity of Mn2FeReO6 compared to similar phases with non-transition-metal ions

in the A sites.

A similar case of a combination of two different magnetic structures with Mn moments,

was previously seen for example in solid solutions of La2-xBixMnO5 with different magnetic

structures for the two extremes of the series (x =0 and x = 2) and in the intermediate members

of the series both magnetic structures coexist and both are necessary simultaneously to

explain the data.26 In Mn2FeReO6 it appears that the presence of significant magnetic

frustration between many magnetic cations in the system, which was prepared under extreme

pressure conditions, requires two different magnetic sub-lattices of Mn cations to stabilize the

11

magnetic structure. The refinement of the crystallographic and magnetic structures of the

PND at 4 K and H = 0 T can be seen in Figure. S8a.

The magnetic structure at 70 K and H = 0 T is the same as that at 4 K and 0T, but with

smaller values of the magnetic moments (Refinement in Fig. S8e). However, at 250 K, it is

clearly seen, by comparison of the PND data at 4 and 250 K at 0T (Figure. S9a), that some of

the magnetic peaks seen at 4 K completely disappear at 250 K. Thus, at 250 K and 0 T the Fe

and Re moments retain the same ferrimagnetic structure as that at 4 K and 0T, while the Mn

cations are no longer magnetically ordered. The refinement of the crystallographic and

magnetic structures at 250 K and 0 T can be seen in Figure S8b, and the schematic view of

the magnetic structure in Figure 4b of the main text. At 250 K and 0 T, the refined Fe

magnetic moments are mx = mz = 2.81(7) μB and the Re moments m x= mz = -0.122(3) μB,

with a ferrimagnetic arrangement similar to the one found in other double perovskites, such

as Sr2FeMoO6 or Sr2FeReO6.27,28 Since at 250 K the Mn sublattice is no longer ordered

magnetically, it cannot effect the Fe and Re moments and the resistance of the sample

decreases compared with that at 4K, 0 T.

Figure S9b shows the comparison of the PND patterns of Mn2FeReO6 at 4 K with 0 T

and 7 T applied magnetic field. The important difference between these data is observed in

the reflection (010) at 22.4o; the intensity of this peak almost disappears completely at 7 T.

The difference found in the refinement is noteworthy: the two different and simultaneous

magnetic sublattices to define the Mn magnetic structure is no longer valid. Now solution 3

(Fx, Gy, Fz) can explain the data together with the ferrimagnetic sublattice of Fe and Re

cations. This means, that the magnetic structure is simplified in the presence of an applied

field. The magnetic moments of Mn are now antiferromagnetically coupled and oriented

along y, since components along x and z are zero (see Figure 4c in the main text for a

12

schematic view). We propose that this Mn magnetic configuration could have a more

significant effect on the half metallicity of sublattice B (since now are all Mn, Fe and Re

moments are aligned in the same direction) than the combination of the Mn magnetic

structures found at 0 T, which would explain the increment of the resistivity when a magnetic

field is applied and the giant positive magnetoresistance. The refinement of the data at 4 K

and 7 T is plotted in Figure S8c.

Finally, Figure S9c shows the difference between the data at 250 K with and without

magnetic field. Both data look very similar and can be explained only with the ferrimagnetic

arrangement of Fe and Re cations. Figure S8d shows the refinement of the structure at 250 K

and 7 T. Table S3, S4, S5 and S6 present the crystallographic and magnetic data after the

refinement of the structures with PND. Tables S3 and S4 collect atomic positions, thermal

parameters, magnetic moments and agreement factors; selected interatomic distances and

bond angles are collected in Tables S5 and S6.

7. First Principles Calculations: Band Structure

As a complement to the computed density of states of Mn2FeReO6 in Figure 5, the

corresponding band structures are shown in Figure S10. The half-metallicity of Mn2FeReO6

is clearly manifested from the band structures as discussed in the main text. In addition, we

expect that this half-metallicity is robust against the possible strong Coulomb interactions not

considered in our calculations, since the interactions are mostly significant on the Mn and Fe

sites but not on Re sites. It is clear from the density of states and the band structure that the

Re-site contributions to the states near the Fermi level are significant.

13

Supplementary Figures

Figure S1 (a) RT-PXD

patterns of Mn2FeReO6 showing a single phase with primary monoclinic or

orthorhombic cell. (b) RT-PXD patterns of Mn2FeReO6 after each TGA-DSC cycle at

temperature (marked beside the XRD pattners) between 450 and 1000 K with step of

50 K. PXD patterns of the as-made sample was added at the bottom for comparison.

The monoclinic phase can be retained up to 850 K upon heating before decomposed

2θ (degree, Cu Kα)10 20 30 40 50 60

Inte

nsi

ty (

a.u

.)

As-made

450 K

500 K

550 K

600 K

650 K

700 K

750 K

800 K

850 K

900 K

950 K

1000 K

(a)

(b)

14

above 900 K. Some relative peak intensitity variation observed on the XRD patterns

were confirmed to be from preferred orientation

Figure S2 Representive ED patterns of Mn2FeReO6 suggesting possible SG of Pn--

(Pnm21, Pn21m, Pnmm) in orthorhombic or P21/n in monoclinic cell.

15

Figure S3 Evolution of the (a) average , (b) bond lengths, and unit

cell volume (V) to the tolerance factor (t) and average A-site cation size ( in

eight coordination environment) in the A2FeReO6 double perovskites with A2 = Ba2,

BaSr, Pb2, Sr2, SrCa, Sr0.5Ca1.5, Ca2, and Mn2. Pb2(S) and Pb2(Q) are for the

Pb2FeReO6 prepared via slow cooling and quenching, respectively. Unit cell volumes

of the tetragonal and monoclinic phases are recalculated for comparison with the

cubic phases.

1.92

1.96

2.00

2.04

2.08

0.9 1.1 1.2 1.3 1.4 1.5

1.90

1.92

1.94

1.96

1.98

2.00

2.02

0.84 0.88 0.92 0.96 1.00

420

440

460

480

500

520

540

t

<R

e-O

> (Å

)<F

e-O

> (Å

)V

(Å

3)

(Å)

Pb

2 (S

)P

b2

(Q)

Ba 2

BaS

r

Sr2

SrC

a

Ca 2

Sr0

.5C

a 1.5

Mn2

Fm-3m

P21/n

I4/m

P21/n

I4/m

Pb

2

(a)

(b)

(c)

Pb

2 (Q

)P

b2

(S)

P21/n I4/m Fm-3m

Fm-3m

16

Figure S4 a) The Mn-K edge spectrum for Mn2FeReO6 compared to those of a

series of standard compound spectra: LaMn3+O3, CaMn4+O3 and Mn2+O; b) The Mn-

K pre-edge spectral region for the same compounds in shown in a. Note the spectra

have been displaced vertically for clarity.

Figure. S5 a) The Fe-K edge spectrum for Mn2FeReO6 compared to those of a

series of standard compound spectra: La2Fe3+VO6, SrFe~4+O3- and LiFe2+PO4,

Fe2+O; b) The Fe-K pre-edge spectral region for the same compounds in shown in a.

Note the spectra have been displaced vertically for clarity and the FeO spectrum has

been scaled down by a factor of 1/2.

17

Figure S6 a) The Re-L3 edges for a series of Re standard compounds in various d-

configurations/valence states: the ~d0-Re7+ compound SrFe3/4Re1/4O6; the ~d1-Re6+

compounds A2MnReO6 (A = Sr and Ba), and ReO3; the ~d2-Re5+ compounds

A’2CrReO6 (A’ = Pb and Ca); and the ~d3-Re4+ compound ReO2. Here, as in the

subsequent figure, spectra have been displaced vertically for clarity. Note the

bimodal A-B structure of WL-5d features and (importantly) the systematic WL

chemical shift to higher energy with increasing nominal Re valence; b) A comparison

of the Re-L3 edge of Mn2FeReO6 to Re6+ and Re5+ standards from the previous

figure.

18

Figure S7 Temperature dependent lattice parameters evolution of (a) a, (b) b, (c) c,

(d) β, and (e) V in Mn2FeReO6 between 10 and 80 K, showing different evolution

linearity below and above 50 K.

90.08

90.09

90.10

90.11

90.12

90.13

90.14

90.15

90.16

10 20 30 40 50 60 70 80

210.64

210.68

210.72

210.76

210.80

T (K)

β(º

)V

(Å3)

5.1914

5.1916

5.1918

5.1920

5.1922

5.3578

5.3580

5.3582

5.3584

5.3586

5.3588

10 20 30 40 50 60 70 80

7.573

7.574

7.575

7.576

T (K)

c(Å

)b

(Å)

a(Å

)

(a)

(b)

(c)

(e)

(d)

19

Figure S8 Experimental (red), calculated (black), and difference (blue) of the PND

patterns of Mn2FeFeO6 collected at a,4 K under 0 T; b, 250 K under 0 T; c, 4 K

under 7 T, d, 250 K under 7 T, e, 70 K under 0 T, and f, 300 K under 0 T.

30 60 90 120

Inte

ns

ity

(a

.u.)

T= 4 K, H = 0 T

2 (deg)30 60 90 120

Inte

ns

ity

(a

.u.)

T= 250 K, H = 0 T

2 (deg)

30 60 90 120

Inte

ns

ity

(a

.u.)

T= 4 K, H = 7 T

2 (deg)30 60 90 120

Inte

ns

ity

(a

.u.)

T = 250 K, H = 7 T

2 (deg)

30 60 90 120

Inte

nsit

y (

a.u

.)

T= 70 K, H = 0 T

2 (deg)30 60 90 120

Inte

ns

ity

(a

.u.)

T = 300 K, H = 0 T

2 (deg)

a b

c d

e f

20

Figure S9 Comparison of the PND patterns a,4 and 250 K under 0 T; b, 4 K under 0

and 7 T; c, 250 K under 0 and 7 T. The peaks with intensity variation are highlighted

by arrows.

20 30 40 50

250 K-0 T

Inte

ns

ity

(a

.u.)

2 (deg)

4 K-0 T

20 30 40 50

4 K-7 T

Inte

ns

ity

(a

.u.)

2 (deg)

4 K-0 T

20 30 40 50

250 K-7 T

Inte

ns

ity

(a

.u.)

2 (deg)

250 K-0 T

a

b

c

21

Figure S10. The band structure of the computed magnetic structure of Mn2FeReO6:

(Left) spin majority, (right) spin minority component. The line width indicates the

weights of Re d-orbitals.

22

Supplementary Tables

Table S1 Structure parameters of Mn2FeReO6 at room temperature refined from the

PSXD data.a

Atom Site x y z Occ. Uiso (×102,Å2)c

Mn 4e -0.0116(7) 0.0530(3) 0.2496(3) 1 0.15(2)

Fe1/Re1 2c 0 1/2 0 0.95(1)/0.05(1)b 0.15(2)

Re2/Fe2 2d 1/2 0 0 0.95(1)/0.05(1)b 0.15(2)

O1 4e 0.1870(16) 0.1823(16) -0.0645(16) 1 0.15(2)

O2 4e 0.1805(16) 0.1961(16) 0.5610(16) 1 0.15(2)

O3 4e 0.3846(12) -0.0558(14) 0.2484(14) 1 0.15(2)

aSpace group P21/n (No. 14), a = 5.20098(2) Å, b = 5.36399(2) Å, c = 7.58904(3) Å, β = 89.95(1)º, V =

211.719(1) Å3, Z = 2, Rp = 5.50%, Rwp = 7.08%, χ2 = 1.65. b The occupancy rate of Fe and Re at the mixed site

was constrained to be unit; c The Uiso parameters were constrained to be refined simultaneously with the same

value.

Table S2 Selected interatomic distances (Å), bond valence sums (BVS), octahedral

distortion parameters (Δ), and bond angles (º) in Mn2FeReO6 at room temperature

MnO6 (Fe1/Re1)O6

Mn -O1

-O2

-O3

BVS

2.097(11)

2.542(10)

2.689(12)

2.150(11)

2.535(10)

2.678(12)

2.142(7)

2.200(8)

2.379(10)

1.97

Fe1/Re1-O1 × 2

-O2 × 2

-O3 × 2

BVS

ΔFe1/Re1 (× 10-4)

(Re2/Fe2)O6

Re2/Fe2-O1 × 2

-O2 × 2

-O3 × 2

2.022(9)

2.020(9)

2. 024(10)

2.022(10)

2.95

0.01

1.961(9)

1.937(9)

2.001(10)

1.966(9)

23

O1-Mn-O1

O2-Mn-O2

O3-Mn-O3

O1-Mn-O2

O1-Mn-O3

O2-Mn-O3

74.2(4)

116.1(4)

125.8(3)

75.0(4)

116.7(4)

125.6(3)

88.3(3)

65.2(3)

70.5(4)

74.0(3)

84.0(4)

124.4(4)

155.5(4)

157.8(4)

69.2(3)

69.4(3)

72.4(3)

104.6(3)

135.2(3)

138.4(3)

66.9(3)

71.8(3)

73.9(3)

103.1(3)

135.3(3)

BVS

ΔRe (× 10-3)

O1-Fe1/Re1-O1

O2-Fe1/Re1-O2

O3-Fe1/Re1-O3

O1-Fe1/Re1-O2

O1-Fe1/Re1-O3

O2-Fe1/Re1-O3

O1-Fe2/Re2-O1

O2- Fe2/Re2-O2

O3- Fe2/Re2-O3

O1- Fe2/Re2-O2

O1- Fe2/Re2-O3

O2- Fe2/Re2-O3

Fe1/Re1-O1-Fe2/Re2

Fe1/Re1-O2-Fe2/Re2

Fe1/Re1-O3-Fe2/Re2

4.51

1.80

180.0(4)

180.0(4)

180.0(3)

89.3(3)

90.7(3)

87.8(4)

92.2(4)

87.2(4)

92.8(4)

180.0(4)

180.0(4)

180.0(3)

87.6(4)

92.4(4)

86.5(4)

93.5(4)

87.4(4)

92.6(4)

139.4(5)

141.4(5)

141.1(6)

24

138.6(3)

Table S3 Structure parameters of Mn2FeReO6a refined from the PND data at 0 T of

applied magnetic field.

T/K

4 70 250 300

P21/n

a/Å 5.19058(14) 5.19344(8) 5.19779(13) 5.20310(7)

b/Å 5.35356(17) 5.35669(8) 5.36054(16) 5.36561(10)

c/Å 7.5717(2) 7.57908(11) 7.5815(2) 7.58927(12)

β/º 89.861(6) 89.884(3) 89.918(8) 90.011(6)

V/Å3 210.403(10) 210.847(5) 211.242(10) 211.876(6)

Mn 4e (x y z)

x -0.0168(19) -0.0096(11) -0.0200(18) -0.0127(11)

y 0.0584(15) 0.0530(6) 0.0600(15) 0.0518(8)

z 0.2282(16) 0.2402(13) 0.2302(19) 0.2412(18)

B/Å2 0.63(7) 0.24(3) 0.76(6) 0.49(3)

25

(Gx, Fy, Gz): (+-+-, 0, +-+-)

Mn Mx/μB 2.05(11) 1.16(14) - -

Mn Mz/μB 1.3(2) 1.07(17) - -

(Fx, Gy, Fz): (0, +-+-, 0)

Mn My/μB -2.91(7) -1.46(11) - -

Fe 2c (0 ½ 0)

B/Å2 0.63(7) 0.24(3) 0.76(6) 0.49(3)

Re 2d (½ 0 0)

B/Å2 0.63(7) 0.24(3) 0.76(6) 0.49(3)

Fe and Re (Fx, Gy, Fz):

(+ +, 0, + +)

Fe Mx/μB = Mz/μB 3.19(7) 3.27(5) 2.81(7) 2.55(7)

Re Mx/μB = Mz/μB -0.143(3) -0.145(2) -0.122(3) -0.112(3)

O1 4e (x y z)

x 0.193(2) 0.1926(12) 0.190(3) 0.185(2)

y 0.191(3) 0.1919(16) 0.193(4) 0.2037(11)

z -0.0690(16) -0.0667(8) -0.0664(19) -0.0680(9)

B/Å2 0.63(7) 0.24(3) 0.76(6) 0.49(3)

O2 4e (x y z)

x 0.175(2) 0.1736(11) 0.180(3) 0.179(2)

y 0.186(3) 0.1865(17) 0.183(4) 0.1755(10)

z 0.5598(16) 0.5602(7) 0.5587(19) 0.5548(9)

B/Å2 0.63(7) 0.24(3) 0.76(6) 0.49(3)

26

O3 4e (x y z)

x 0.3808(10) 0.3799(5) 0.3821(9) 0.3783(6)

y -0.0595(12) -0.0580(5) -0.0553(11) -0.0536(6)

z 0.248(2) 0.2489(11) 0.249(3) 0.2445(16)

B/Å2 0.63(7) 0.24(3) 0.76(6) 0.49(3)

Reliability factors

χ2 0.942 1.16 0.862 1.38

Rp 5.85 4.41 6.21 3.96

Rwp 7.43 5.26 7.95 4.87

R(Mn)mag 9.54/10.6 14.6/20.3 - -

R(Fe/Re)mag 9.92 12.9 12.2 10.2

aSpace group P21/n (No. 14). b The occupancy rate of Fe and Re at the mixed site was constrained to be unit and

fixed to synchrotron x-ray diffraction results of 0.95/0.05. cBiso parameters were constrained to be refined

simultaneously with the same value for each set of data.

Table S4 Structure parameters of Mn2FeReO6a refined from the PND data at 7 T of

applied magnetic field.

T/K 4 250

P21/n

a/Å 5.19466(13) 5.20209(11)

b/Å 5.35709(16) 5.36311(14)

c/Å 7.5736(2) 7.58379(18)

β/º 89.863(6) 89.906(7)

V/Å3 210.760(10) 211.583(9)

27

Mn 4e (x y z)

x -0.0172(19) -0.0182(17)

y 0.0613(14) 0.0620(13)

z 0.237(2) 0.2295(17)

B/Å2 0.56(7) 0.82(5)

(Fx, Gy, Fz): (0,+-+-,0)

Mn My/μB -2.93(5) -

Fe 2c (0 ½ 0)

B/Å2 0.56(7) 0.82(5)

Re 2d(½ 0 0)

B/Å2 0.56(7) 0.82(5)

Fe and Re (Fx, Gy, Fz): (+

+,0,+ +)

Fe Mx/μB= Mz/μB 3.69(7) 3.25(6)

Re Mx/μB= Mz/μB -0.155(3) -0.138(2)

O1 4e (x y z)

x 0.198(2) 0.192(2)

y 0.186(3) 0.193(3)

z -0.0677(16) -0.0656(17)

B/Å2 0.56(7) 0.82(5)

O2 4e (x y z)

x 0.173(2) 0.179(2)

y 0.191(3) 0.185(3)

28

z 0.5571(16) 0.5578(16)

B/Å2 0.56(7) 0.82(5)

O3 4e (x y z)

x 0.3772(10) 0.3778(8)

y -0.0578(12) -0.0541(10)

z 0.249(2) 0.254(2)

B/Å2 0.56(7) 0.82(5)

Reliability factors

χ2 0.982 0.961

Rp 5.77 5.40

Rwp 7.40 6.90

R(Mn)mag 21.0 -

R(Fe/Re)mag 7.81 11.2

aSpace group P21/n (No. 14). b The occupancy rate of Fe and Re at the mixed site was constrained to be unit and

fixed to x-ray diffraction results of 0.95/0.05. cBiso parameters were constrained to be refined simultaneously

with the same value.

Table S5: Main bond distances, selected angles (º) and Bond Valence Sum Results

determined for Mn2FeReO6 refined from the PND data at 0 T of applied magnetic

field.

T/K 4 70 250 300

MnO8 Octahedra

Mn-O1 2.597(17) 2.598(20) 2.600(20) 2.689(12)

Mn-O1 2.021(18) 2.041(21) 2.041(21) 2.100(12)

Mn-O1 2.531(17) 2.528(20) 2.529(20) 2.509(12)

Mn-O2 2.789(17) 2.779(20) 2.779 (21) 2.6644(12)

Mn-O2 2.228(18) 2.224(21) 2.224(21) 2.1526(12)

Mn-O2 2.460(17) 2.454(20) 2.455(20) 2.5912(11)

Mn-O3 2.164(11) 2.183(10) 2.184(10) 2.1117(11)

Mn-O3 2.171(10) 2.189(10) 2.189(10) 2.2324(11)

29

2.462(6) 2.463(8) 2.464(8) 2.474(4)

FeO6 Octahedra

Fe-O1 ( × 2) 2.001(17) 1.983(20) 1.984(19) 1.929(7)

Fe-O2 (× 2) 2.010(14) 1.980(17) 1.981(17) 1.962(9)

Fe-O3 (× 2) 2.029(15) 2.022(21) 2.022( 21) 2.060(11)

2.013(6) 1.995(8) 1.996(8) 1.984(4)

ReO6 Octahedra

Re-O1 (× 2) 1.966(14) 1.979(17) 1.981(17) 2.036(9)

Re-O2 (× 2) 1.963(17) 1.990(20) 1.991(20) 2.018(7)

Re-O3 (× 2) 2.005 (15) 2.006(21) 2.006(21) 1.982(11)

1.978(6) 1.992(8) 1.992(8) 2.012(4)

Angles around O

Fe-O1-Re 140.0(6) 140.7(8) 140.7(8) 140.9(3)

Fe-O2-Re 139.6(6) 140.1(8) 140.1(8) 139.8(3)

Fe-O3-Re 139.6(6) 140.5(9) 140.5(9) 139.7(5)

139.7 140.4 140.4 140.1

BVS

Mn 1.97(3) 1.92( 4) 1.92( 4) 1.79(2)

Fe 3.02(5) 3.17(7) 3.17( 7) 3.31(3)

Re 4.36(7) 4.20(9) 4.20( 9) 3.99(4)

Table S6: Main bond distances (Å) and selected angles (º) determined for

Mn2FeReO6 refined from the PND data at 7T of applied magnetic field.

4 K 250 K

MnO8 Octahedra

Mn-O1 2.649(17) 2.587(17)

Mn-O1 2.074(18)

2.0210

2.058(17)

30

Mn-O1 2.486(17) 2.531(16)

Mn-O2 2.712(18) 2.774(17)

Mn-O2 2.215(18) 2.248(17)

Mn-O2 2.492(17) 2.455(16)

Mn-O3 2.147(11) 2.160(10)

Mn-O3 2.170(10) 2.188 (9)

2.462(6) 2.468(6)

FeO6 Octahedra

Fe-O1 (× 2) 2.032(15) 1.989(15)

Fe-O2 (× 2) 2.029(12) 1.991(12)

Fe-O3 (× 2) 2.030(14) 1.993(14)

2.031(6) 1.991(6)

ReO6 Octahedra

Re-O1 (× 2) 1.932(12) 1.972(12)

Re-O2 (× 2) 1.933(15) 1.979(15)

Re-O3 (× 2) 2.013(14) 2.048(13)

1.959(6) 1.999(6)

Angles around O

Fe-O1-Re 140.5(5) 141.2(6)

Fe-O2-Re 140.6(6) 140.5(6)

Fe-O2-Re 138.9(6) 139.5(6)

140.0 140.4

BVS

Mn 1.82(33) 1.90(3)

Fe 2.88(4) 3.21(5)

Re 4.61(7) 4.13(6)

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