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LSCO
FeLSAO
ws=2μmds=65nmwf=400nmdf=60nm
Fe
LSCO
LSAO
1 2
ds
dfws
wf
Microbridges with Magnetic Strip
Suppression of superconductivity directly underneath Fe strip
V. Peña et al, PRB. 69, 224502 (2004)Buzdin, RMP. 77, 77935 (2005)
LTS HTS
0 5 10 150.0
0.1
0.2
0.3
0.4
0.5
0.6
8.0K 10.0K 12.0K 14.0K 16.0K 18.0K 20.0K 22.0K
Cur
rent
(m
A)
Voltage (mV)0 5 10 15
0
20
40
60
80
8.0K 10.0K 12.0K 14.0K 16.0K 18.0K 20.0K 22.0K
dV/d
I (
)
Voltage ( mV )
6 8 10 12 14 16 18 20 22 240
40
80
120
160
200 I
c
I c ( A
)
Temperature ( K )
30
40
50
60
70
RN
RN
(
)
8 10 12 14 16 18 20 220
2
4
6
8
10 Vc = I
cR
N
P 250 nW @ 8K
Vc
( m
V )
Temperature ( K )
Junctions with high IcRN-products
Junctions are SNS type
0.0 0.2 0.4 0.6 0.8 1.00.0
0.2
0.4
0.6
0.8
1.0
L / n 4I c/I
c(0)
T/Tc
Fe-Bridge Cu-Bridge Bridge ( 1 - T/T
c )
de GennesIc(T,L)
Delin and Kleinsasser, Supercond. Sci. Technol. 9, p227, 1996
SNS junctions provide easy control over the junctions parameters (Ic and
RN values).
SNS Junctions
wd
LR NN
Results on 300nm wide Fe strip
5 10 15 20 25 30 35 40 45 500
5
10
15
20
25
30
35
Without Fe With Fe, 300nm
La1.85Sr
0.15CuO
4
Res
ista
nce
( k
)
Temperature ( K )
14 16 18 20 22 24 26 280
50
100
150
200
250
300
350
400La
1.85Sr
0.15CuO
4
Without Fe With Fe, 300nm
Res
ista
nce
(
)
Temperature ( K )
A400
B300
C200
D100
NO Fe A&B
NO Fe C&D
-100-80 -60 -40 -20 0 20 40 60 80 100-1000
-800-600-400-200
0200400600800
1000La
1.85Sr
0.15CuO
4
T @ 15.00K
IcRN ~ 20 mV
Without Fe With Fe, 300nm
Ic ~ 20 A
Jc ~ 15.4 kA/cm2
RN ~ 1 k
N ~ 65m-cmC
urre
nt (
A
)
Voltage ( mV )
0 3 6 9 12 150
20
40
60
80
100
120La
1.85Sr
0.15CuO
4
5.0 K 7.0 K 9.0 K 11. 0K 13.0 K 15.0 K 17.0 K 19.0 K
C
urr
ent
( A
)
Voltage ( mV )
4 6 8 10 12 14 16 18 200
10
20
30
40
50
60La
1.85Sr
0.15CuO
4
IC = I
C0 ( 1 - T / T
c ) 2
I C (
A )
Temperature ( K )
Ic [1μV] criteria
-80 -60 -40 -20 0 20 40 60 80-10-8-6-4-202468
10La
1.85Sr
0.15CuO
4
@18K
I C (
A
)
B ( G )
+Ic
-Ic
22
0
0 46.045
7.20mww
G
mG
B fs
-24 -16 -8 0 8 16 24
-400
-200
0
200
400
600 I
Cu
rre
nt (A
)
Voltage (V)
0.00
0.05
0.10
0.15
0.20
0.25
0.30
0.35
0.40
dV/dI2 GHz
0.0 dBm
dV
/dI ()
VV AC 401
nmwefff 230