Magnetic Josephson junctions (MJJs) are a special class of hybrid systems where antagonistic correlations coexist, thus providing a key for advances in weak superconductivity, superconducting spintronics, and quantum computation. So far, the memory properties of MJJs have been mostly investigated in view of digital electronics and for spintronic devices at liquid-helium temperature. At the operating temperature of quantum circuits, a magnetic order can rise in a superconductor (S) at the S/ferromagnet (F) interface, i.e., the inverse proximity effect (IPE), thus leading to a significant modification of the magnetic field patterns in MJJs. In this work, we have carried out a comparative investigation of the magnetic behavior of tunnel MJJs with a strong ferromagnetic layer inserted in the layout of both Nb and Al JJs, respectively. The comparative analysis validates the crucial role of the temperature, the fundamental scaling energies of S/F coupling systems, and the transparency of the S/F interface. This investigation points out that the IPE is a key aspect to consider when designing tunnel MJJs operating well below 4 K and thus in the perspective of hybrid superconducting quantum architectures.

1.
F. S.
Bergeret
,
A. F.
Volkov
, and
K. B.
Efetov
, “
Odd triplet superconductivity and related phenomena in superconductor-ferromagnet structures
,”
Rev. Mod. Phys.
77
,
1321
(
2005
).
2.
A. I.
Buzdin
, “
Proximity effects in superconductor-ferromagnet heterostructures
,”
Rev. Mod. Phys.
77
,
935
(
2005
).
3.
A. A.
Golubov
,
M. Y.
Kupriyanov
, and
E.
Il’ichev
, “
The current-phase relation in josephson junctions
,”
Rev. Mod. Phys.
76
,
411469
(
2004
).
4.
V. V.
Ryazanov
,
V. A.
Oboznov
,
A. Y.
Rusanov
,
A. V.
Veretennikov
,
A. A.
Golubov
, and
J.
Aarts
, “
Coupling of two superconductors through a ferromagnet: Evidence for a π junction
,”
Phys. Rev. Lett.
86
,
2427
(
2001
).
5.
V. A.
Oboznov
,
V. V.
Bol’ginov
,
A. K.
Feofanov
,
V. V.
Ryazanov
, and
A. I.
Buzdin
, “
Thickness dependence of the josephson ground states of superconductor–ferromagnet–superconductor junctions
,”
Phys. Rev. Lett.
96
,
197003
(
2006
).
6.
J. W. A.
Robinson
,
S.
Piano
,
G.
Burnell
,
C.
Bell
, and
M. G.
Blamire
, “
Critical current oscillations in strong ferromagnetic π junctions
,”
Phys. Rev. Lett.
97
,
177003
(
2006
).
7.
N. O.
Birge
, and
N.
Satchell
, “
Ferromagnetic materials for josephson π junctions
,”
APL Mater.
12
,
041105
(
2024
).
8.
N.
Banerjee
,
C. B.
Smiet
,
R. G. J.
Smits
,
A.
Ozaeta
,
F. S.
Bergeret
,
M. G.
Blamire
, and
J. W. A.
Robinson
, “
Evidence for spin selectivity of triplet pairs in superconducting spin valves
,”
Nat. Commun.
5
,
3048
(
2014
).
9.
J. W. A.
Robinson
,
J. D. S.
Witt
, and
M. G.
Blamire
, “
Controlled injection of spin-triplet supercurrents into a strong ferromagnet
,”
Science
329
,
59
(
2010
).
10.
C.
Klose
,
T. S.
Khaire
,
Y.
Wang
,
W. P.
Pratt
,
N. O.
Birge
,
B. J.
McMorran
,
T. P.
Ginley
,
J. A.
Borchers
,
B. J.
Kirby
,
B. B.
Maranville
, and
J.
Unguris
, “
Optimization of spin-triplet supercurrent in ferromagnetic josephson junctions
,”
Phys. Rev. Lett.
108
,
127002
(
2012
).
11.
H. G.
Ahmad
,
M.
Minutillo
,
R.
Capecelatro
,
A.
Pal
,
R.
Caruso
,
G.
Passarelli
,
M. G.
Blamire
,
F.
Tafuri
,
P.
Lucignano
, and
D.
Massarotti
, “
Coexistence and tuning of spin-singlet and triplet transport in spin-filter josephson junctions
,”
Commun. Phys.
5
,
2
(
2022
).
12.
J.
Linder
and
J. W. A.
Robinson
, “
Superconducting spintronics
,”
Nat. Phys.
11
,
307
(
2015
).
13.
M.
Eschrig
, “
Spin-polarized supercurrents for spintronics: A review of current progress,
Rep. Prog. Phys.
78
,
104501
(
2015
).
14.
I. I.
Soloviev
,
N. V.
Klenov
,
S. V.
Bakurskiy
,
M. Y.
Kupriyanov
,
A. L.
Gudkov
, and
A. S.
Sidorenko
, “
Beyond moore’s technologies: Operation principles of a superconductor alternative
,”
Beilstein J. Nanotechnol.
8
,
2689
(
2017
).
15.
R.
Cai
,
I.
Žutić
, and
W.
Han
, “
Superconductor/ferromagnet heterostructures: A platform for superconducting spintronics and quantum computation
,”
Adv. Quantum Technol.
6
,
2200080
(
2023
).
16.
A. K.
Feofanov
,
V. A.
Oboznov
,
V. V.
Bol’ginov
,
J.
Lisenfeld
,
S.
Poletto
,
V. V.
Ryazanov
,
A. N.
Rossolenko
,
M.
Khabipov
,
D. Z.
Balashov
,
P. N.
Dmitriev
,
V. P.
Koshelets
, and
A. V.
Ustinov
, “
Implementation of superconductor/ferromagnet/ superconductor π-shifters in superconducting digital and quantum circuits
,”
Nat. Phys.
6
,
593
(
2010
).
17.
A. V.
Shcherbakova
,
K. G.
Fedorov
,
K. V.
Shulga
,
V. V.
Ryazanov
,
V. V.
Bolginov
,
V. A.
Oboznov
,
S. V.
Egorov
,
V. O.
Shkolnikov
,
M. J.
Wolf
,
D.
Beckmann
, and
A. V.
Ustinov
, “
Fabrication and measurements of hybrid Nb/Al josephson junctions and flux qubits with π-shifters
,”
Supercond. Sci. Technol.
28
,
025009
(
2015
).
18.
T.
Yamashita
,
S.
Kim
,
H.
Kato
,
W.
Qiu
,
K.
Semba
,
A.
Fujimaki
, and
H.
Terai
, “
Π phase shifter based on NbN-based ferromagnetic josephson junction on a silicon substrate
,”
Sci. Rep.
10
,
13687
(
2020
).
19.
S.
Kawabata
,
S.
Kashiwaya
,
Y.
Asano
,
Y.
Tanaka
, and
A.
Golubov
, “
Macroscopic quantum dynamics of π junctions with ferromagnetic insulators
,”
Phys. Rev. B
74
,
180502
(
2006
).
20.
S.
Kim
,
L. V.
Abdurakhimov
,
D.
Pham
,
W.
Qiu
,
H.
Terai
,
S.
Ashhab
,
S.
Saito
,
T.
Yamashita
, and
K.
Semba
, Superconducting flux qubit with ferromagnetic Josephson π junction operating at zero magnetic field, arXiv, p. 2401.14597 (
2024
).
21.
H.
Sickinger
,
A.
Lipman
,
M.
Weides
,
R. G.
Mints
,
H.
Kohlstedt
,
D.
Koelle
,
R.
Kleiner
, and
E.
Goldobin
, “
Experimental evidence of a π josephson junction
,”
Phys. Rev. Lett.
109
,
107002
(
2012
).
22.
T. I.
Larkin
,
V. V.
Bol’ginov
,
V. S.
Stolyarov
,
V. V.
Ryazanov
,
I. V.
Vernik
,
S. K.
Tolpygo
, and
O. A.
Mukhanov
, “
Ferromagnetic josephson switching device with high characteristic voltage
,”
Appl. Phys. Lett.
100
,
222601
(
2012
).
23.
M.
Weides
,
M.
Kemmler
,
E.
Goldobin
,
D.
Koelle
,
R.
Kleiner
,
H.
Kohlstedt
, and
A.
Buzdin
, “
High quality ferromagnetic 0 and π josephson tunnel junctions
,”
Appl. Phys. Lett.
89
,
122511
(
2006
).
24.
L.
Parlato
,
R.
Caruso
,
A.
Vettoliere
,
R.
Satariano
,
H. G.
Ahmad
,
A.
Miano
,
D.
Montemurro
,
D.
Salvoni
,
G.
Ausanio
,
F.
Tafuri
,
G. P.
Pepe
,
D.
Massarotti
, and
C.
Granata
, “
Characterization of scalable josephson memory element containing a strong ferromagnet,
J. Appl. Phys.
127
,
193901
(
2020
).
25.
A.
Vettoliere
,
R.
Satariano
,
R.
Ferraiuolo
,
L.
Di Palma
,
H. G.
Ahmad
,
G.
Ausanio
,
G. P.
Pepe
,
F.
Tafuri
,
D.
Montemurro
,
C.
Granata
,
L.
Parlato
, and
D.
Massarotti
, “
Aluminum-ferromagnetic josephson tunnel junctions for high-quality magnetic switching devices
,”
Appl. Phys. Lett.
120
,
262601
(
2022
).
26.
K.
Senapati
,
M. G.
Blamire
, and
Z. H.
Barber
, “
Spin-filter josephson junctions
,”
Nat. Mater.
10
,
849
(
2011
).
27.
H. G.
Ahmad
,
R.
Caruso
,
A.
Pal
,
G.
Rotoli
,
G. P.
Pepe
, and
M. G.
Blamire
,
F.
Tafuri
and
D.
Massarotti
, “
electrodynamics of highly spin-polarized tunnel josephson junctions
,”
Phys. Rev. Appl.
13
,
014017
(
2020
).
28.
D.
Massarotti
,
A.
Pal
,
G.
Rotoli
,
L.
Longobardi
,
M. G.
Blamire
, and
F.
Tafuri
, “
Macroscopic quantum tunneling in spin filter ferromagnetic josephson junctions
,”
Nat. Commun.
6
,
7376
(
2015
).
29.
D.
Massarotti
,
H. G.
Ahmad
,
R.
Satariano
,
R.
Ferraiuolo
,
L.
Di Palma
,
P.
Mastrovito
,
G.
Serpico
,
A.
Levochkina
,
R.
Caruso
,
A.
Miano
,
M.
Arzeo
,
G.
Ausanio
,
C.
Granata
,
P.
Lucignano
,
D.
Montemurro
,
L.
Parlato
,
A.
Vettoliere
, and
R.
Fazio
,
O.
Mukhanov
,
G.
Pepe
, and
F.
Tafuri
, “
A feasible path for the use of ferromagnetic josephson junctions in quantum circuits: The ferro-transmon
,”
Fiz. Nizk.Temp.
49
,
871
(
2023
) [
Low Temp. Phys.
49, 794 (2023)].
30.
H. G.
Ahmad
,
V.
Brosco
,
A.
Miano
,
L.
Di Palma
,
M.
Arzeo
,
D.
Montemurro
,
L.
Lucignano
,
G. P.
Pepe
,
F.
Tafuri
,
R.
Fazio
, and
D.
Massarotti
, “
Hybrid ferromagnetic transmon qubit: Circuit design, feasibility, and detection protocols for magnetic fluctuations
,”
Phys. Rev. B
105
,
214522
(
2022
).
31.
R.
Satariano
,
L.
Parlato
,
A.
Vettoliere
,
R.
Caruso
,
H. G.
Ahmad
,
A.
Miano
,
L.
Di Palma
,
D.
Salvoni
,
D.
Montemurro
,
C.
Granata
,
G.
Lamura
,
F.
Tafuri
,
G. P.
Pepe
,
D.
Massarotti
, and
G.
Ausanio
, “
Inverse magnetic hysteresis of the josephson supercurrent: Study of the magnetic properties of thin niobium/permalloy Fe20Ni80 interfaces
,”
Phys. Rev. B
103
,
224521
(
2021
).
32.
R.
Satariano
,
A. F.
Volkov
,
H. G.
Ahmad
,
L.
Di Palma
,
R.
Ferraiuolo
,
A.
Vettoliere
,
C.
Granata
,
D.
Montemurro
,
L.
Parlato
,
G. P.
Pepe
,
F.
Tafuri
,
G.
Ausanio
, and
D.
Massarotti
, “
Nanoscale spin ordering and spin screening effects in tunnel ferromagnetic josephson junctions
,”
Commun. Mater.
5
,
67
(
2024
).
33.
F. S.
Bergeret
,
A. F.
Volkov
, and
K. B.
Efetov
, “
Induced ferromagnetism due to superconductivity in superconductor-ferromagnet structures
,”
Phys. Rev. B
69
,
174504
(
2004
).
34.
F. S.
Bergeret
,
A. F.
Volkov
, and
K. B.
Efetov
, “
Spin screening of magnetic moments in superconductors
,”
EPL
66
,
111
(
2004
).
35.
A. F.
Volkov
,
F. S.
Bergeret
, and
K. B.
Efetov
, “
Spin polarization and orbital effects in superconductor-ferromagnet structures
,”
Phys. Rev. B
99
,
144506
(
2019
).
36.
S. M.
Dahir
,
A. F.
Volkov
, and
I. M.
Eremin
, “
Phase-dependent spin polarization of cooper pairs in magnetic josephson junctions
,”
Phys. Rev. B
100
,
134513
(
2019
).
37.
P.
Krantz
,
M.
Kjaergaard
,
F.
Yan
,
T. P.
Orlando
,
S.
Gustavsson
, and
W. D.
Oliver
, “
A quantum engineer’s guide to superconducting qubits,
Appl. Phys. Rev.
6
,
021318
(
2019
).
38.
B. M.
Niedzielski
,
E. C.
Gingrich
,
R.
Loloee
,
W. P.
Pratt
, and
N. O.
Birge
, “
S/F/S josephson junctions with single-domain ferromagnets for memory applications
,”
Supercond. Sci. Technol.
28
,
085012
(
2015
).
39.
A. E.
Qader
,
R. K.
Singh
,
S. N.
Galvin
,
L.
Yu
,
J. M.
Rowell
, and
N.
Newman
, “
Switching at small magnetic fields in josephson junctions fabricated with ferromagnetic barrier layers
,”
Appl. Phys. Lett.
104
,
022602
(
2014
).
40.
I.
Siddiqi
, “
Engineering high-coherence superconducting qubits
,”
Nat. Rev. Mater.
6
,
875
(
2021
).
41.
W.
Oliver
, and
P.
Welander
, “
Materials in superconducting quantum bits
,”
MRS Bulletin
38
,
816
(
2013
).
42.
A.
Osman
,
J.
Simon
,
A.
Bengtsson
,
S.
Kosen
,
P.
Krantz
,
D.
Lozano
,
M.
Scigliuzzo
,
P.
Delsing
,
J. bylander, and A. fadavi roudsari, Simplified josephson-junction fabrication process for reproducibly high-performance superconducting qubits
,”
Appl. Phys. Lett.
118
,
064002
(
2021
).
43.
A.
Anferov
,
K.-H.
Lee
,
F.
Zhao
,
J.
Simon
, and
D. I.
Schuster
, “
Improved coherence in optically defined niobium trilayer-junction qubits
,”
Phys. Rev. Appl.
21
,
024047
(
2024
).
44.
L. S.
Uspenskaya
,
O. A.
Tikhomirov
,
S. I.
Bozhko
,
S. V.
Egorov
, and
A. A.
Chugunov
,
Domain structure and magnetization of the permalloy/niobium bilayers
,”
J. Appl. Phys.
16
,
163907
(
2013
).
45.
M.
Volmer
, and
J.
Neamtu
, “
Simulated and measured hysteresis curves for thin films
,”
Physica B
372
,
198
(
2006
).
46.
R. P.
Cowburn
, “
Property variation with shape in magnetic nanoelements
,”
J. Phys. D
33
,
R1
(
2000
).
47.
M.
Schneider
and
H.
Hoffmann
, “
Magnetization loops of submicron ferromagnetic permalloy dot arrays
,”
J. Appl. Phys.
86
,
4539
(
1999
).
48.
A. I.
Gubin
,
K. S.
Il’in
,
S. A.
Vitusevich
,
M.
Siegel
, and
N.
Klein
, “
Dependence of magnetic penetration depth on the thickness of superconducting Nb thin films
,”
Phys. Rev. B
72
,
064503
(
2005
).
49.
A.
Vettoliere
,
R.
Satariano
,
R.
Ferraiuolo
,
L.
Di Palma
,
H. G.
Ahmad
,
G.
Ausanio
,
G. P.
Pepe
,
F.
Tafuri
,
D.
Massarotti
,
D.
Montemurro
,
C.
Granata
, and
L.
Parlato
, “
High-quality ferromagnetic josephson junctions based on aluminum electrodes
,”
Nanomaterials
12
,
4155
(
2022
).
50.
A.
Barone
and
G.
Paterno
,
Physics and Application of the Josephson Effect
, (
John Wiley & Sons
,
1982
).
51.
O. M.
Kapran
,
T.
Golod
,
A.
Iovan
,
A. S.
Sidorenko
,
A. A.
Golubov
, and
V. M.
Krasnov
, “
Crossover between short- and long-range proximity effects in superconductor/ferromagnet/superconductor junctions with Ni-based ferromagnets
,”
Phys. Rev. B
103
,
094509
(
2021
).
52.
V. N.
Gubankov
,
M. P.
Lisitskii
,
I. L.
Serpuchenko
,
F. N.
Sklokin
, and
M. V.
Fistul
, “
Influence of trapped abrikosov vortices on the critical current of the josephson tunnel junction
,”
Supercond. Sci. Technol.
5
,
168
(
1992
).
53.
C.
Cirillo
,
S.
Voltan
,
E. A.
Ilyina
,
J. M.
Hernàndez
,
A.
Garcìa-Santiago
,
J.
Aarts
, and
C.
Attanasio
, “
Long-range proximity effect in Nb-based heterostructures induced by a magnetically inhomogeneous permalloy layer
,”
New J. Phys.
19
,
023037
(
2017
).
54.
S. V.
Bakurskiy
,
N. V.
Klenov
,
I. I.
Soloviev
,
V. V.
Bol’ginov
,
V. V.
Ryazanov
,
I. V.
Vernik
,
O. A.
Mukhanov
,
M. Y.
Kupriyanov
, and
A. A.
Golubov
, “
Theoretical model of superconducting spintronic SIsFS devices
,”
App. Phys. Lett.
102
,
192603
(
2013
).
55.
T. S.
Khaire
,
W. P.
Pratt
, and
N. O.
Birge
, “
Critical current behavior in josephson junctions with the weak ferromagnet PdNi
,”
Phys. Rev. B
79
,
094523
(
2009
).
56.
G.
Marchegiani
,
L.
Amico
, and
G.
Catelani
, “
Quasiparticles in superconducting qubits with asymmetric junctions
,”
PRX Quantum
3
,
040338
(
2022
).
57.
S. V.
Bakurskiy
,
N. V.
Klenov
,
I. I.
Soloviev
,
M. Y.
Kupriyanov
, and
A. A.
Golubov
, “
Theory of supercurrent transport in SIsFS josephson junctions
,”
Phys. Rev. B
88
,
144519
(
2013
).
58.
H. G.
Ahmad
,
V.
Brosco
,
A.
Miano
,
L.
Di Palma
,
M.
Arzeo
,
R.
Satariano
,
R.
Ferraiuolo
,
P.
Lucignano
,
A.
Vettoliere
,
C.
Granata
,
L.
Parlato
,
G.
Ausanio
,
D.
Montemurro
,
G. P.
Pepe
,
R.
Fazio
,
F.
Tafuri
, and
D.
Massarotti
, “
Competition of quasiparticles and magnetization noise in hybrid ferromagnetic transmon qubits
,”
IEEE Trans. Appl. Supercond.
33
,
1
(
2023
).
59.
J.
Xia
,
V.
Shelukhin
,
M.
Karpovski
,
A.
Kapitulnik
, and
A.
Palevski
, “
Inverse proximity effect in superconductor-ferromagnet bilayer structures
,”
Phys. Rev. Lett.
102
,
087004
(
2009
).
60.
Y.
Khaydukov
,
B.
Nagy
,
J. H.
Kim
,
T.
Keller
,
A.
Rühm
,
Y. V.
Nikitenko
,
K. N.
Zhernenkov
,
J.
Stahn
,
L. F.
Kiss
,
A.
Csik
,
L.
Bottyán
, and
V. L.
Aksenov
, “
On the feasibility to study inverse proximity effect in a single S/F bilayer by polarized neutron reflectometry
,”
JETP Lett.
98
,
107
(
2013
).
61.
M. G.
Flokstra
,
R.
Stewart
,
N.
Satchell
,
G.
Burnell
,
H.
Luetkens
,
T.
Prokscha
,
A.
Suter
,
E.
Morenzoni
, and
S. L.
Lee
, “
Meissner screening as a probe for inverse superconductor-ferromagnet proximity effects
,”
Phys. Rev. B
104
,
L060506
(
2021
).
62.
J. W. A.
Robinson
,
S.
Piano
,
G.
Burnell
,
C.
Bell
, and
M. G.
Blamire
, “
Critical current oscillations in strong ferromagnetic π junctions
,”
Phys. Rev. Lett.
97
,
177003
(
2006
).
63.
A. F.
Mayadas
,
J. F.
Janak
, and
A.
Gangulee
, “
Resistivity of permalloy thin films,
J. Appl. Phys.
45
,
2780
(
1974
).
64.
C.
Bell
,
R.
Loloee
,
G.
Burnell
, and
M. G.
Blamire
, “
Characteristics of strong ferromagnetic josephson junctions with epitaxial barriers
,”
Phys. Rev. B
71
,
180501
(
2005
).
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