We have measured the synaptic properties of a magnetic Josephson junction (MJJ) consisting of a barrier of amorphous Ge containing size-selected Fe nanoclusters between two Nb electrodes. We show that the critical current of the device varies with the magnetic order of the clusters and that the magnetic order can be tuned in a quasi-analog way with short electrical pulses of 16 pJ applied through the device. This is the first demonstration of critical current tuning via magnetic order in a nano-clustered MJJ in a material system other than SiMn. This result eliminates the need for a postdeposition annealing step for synaptic MJJs in neuromorphic applications and opens new options to optimize materials, which has the potential to improve the performance of the MJJs and provide a better understanding of the physics of the device.
REFERENCES
1.
M. L.
Schneider
, C. A.
Donnelly
, and S. E.
Russek
, “Tutorial: High-speed low-power neuromorphic systems based on magnetic Josephson junctions
,” J. Appl. Phys.
124
, 161102
(2018
). 2.
P.
Crotty
, D.
Schult
, and K.
Segall
, “Josephson junction simulation of neurons
,” Phys. Rev. E
82
, 011914
(2010
). 3.
K.
Segall
, M.
Legro
, S.
Kaplan
, O.
Svitelskiy
, S.
Khadka
, P.
Crotty
, and D.
Schult
, “Synchronization dynamics on the picosecond time scale in coupled Josephson junction neurons
,” Phys. Rev. E
95
, 032220
(2017
). 4.
W.
Maass
, “Networks of spiking neurons: The third generation of neural network models
,” Neural Netw.
10
, 1659
–1671
(1997
). 5.
Y.
Yamanashi
, K.
Umeda
, and N.
Yoshikawa
, “Pseudo sigmoid function generator for a superconductive neural network
,” IEEE Trans. Appl. Supercond.
23
, 1701004
(2013
). 6.
F.
Chiarello
, P.
Carelli
, M. G.
Castellano
, and G.
Torrioli
, “Artificial neural network based on SQUIDs: Demonstration of network training and operation
,” Supercond. Sci. Technol.
26
, 125009
(2013
). 7.
A. E.
Schegolev
, N. V.
Klenov
, I. I.
Soloviev
, and M. V.
Tereshonok
, “Adiabatic superconducting cells for ultra-low-power artificial neural networks
,” Beilstein J. Nanotechnol.
7
, 1397
–1403
(2016
). 8.
N. V.
Klenov
, A. E.
Schegolev
, I. I.
Soloviev
, S. V.
Bakurskiy
, and M. V.
Tereshonok
, “Energy efficient superconducting neural networks for high-speed intellectual data processing systems
,” IEEE Trans. Appl. Supercond.
28
, 1
–6
(2018
). 9.
R.
Cheng
, U. S.
Goteti
, and M. C.
Hamilton
, “Spiking neuron circuits using superconducting quantum phase-slip junctions
,” J. Appl. Phys.
124
, 152126 (2018
).10.
I. I.
Soloviev
, A. E.
Schegolev
, N. V.
Klenov
, S. V.
Bakurskiy
, M. Y.
Kupriyanov
, M. V.
Tereshonok
, A. V.
Shadrin
, V. S.
Stolyarov
, and A. A.
Golubov
, “Adiabatic superconducting artificial neural network: Basic cells
,” J. Appl. Phys.
124
, 152113
(2018
). 11.
M. L.
Schneider
, C. A.
Donnelly
, S. E.
Russek
, B.
Baek
, M. R.
Pufall
, P. F.
Hopkins
, P. D.
Dresselhaus
, S. P.
Benz
, and W. H.
Rippard
, “Ultralow power artificial synapses using nanotextured magnetic Josephson junctions
,” Sci. Adv.
4
, e1701329
(2018
). 12.
M. L.
Schneider
, C. A.
Donnelly
, I. W.
Haygood
, A.
Wynn
, S. E.
Russek
, M. A.
Castellanos-Beltran
, P. D.
Dresselhaus
, P. F.
Hopkins
, M. R.
Pufall
, and W. H.
Rippard
, “Synaptic weighting in single flux quantum neuromorphic computing
,” Sci. Rep.
10
, 1
(2020
). 13.
B.
Baek
, M. L.
Schneider
, M. R.
Pufall
, and W. H.
Rippard
, “Anomalous supercurrent modulation in Josephson junctions with Ni-based barriers
,” IEEE Trans. Appl. Supercond.
28
, 1–5 (2018
).14.
J. A.
Glick
, M. A.
Khasawneh
, B. M.
Niedzielski
, R.
Loloee
, W. P.
Pratt
, N. O.
Birge
, E. C.
Gingrich
, P. G.
Kotula
, and N.
Missert
, “Critical current oscillations of elliptical Josephson junctions with single-domain ferromagnetic layers
,” J. Appl. Phys.
122
, 133906
(2017
). 15.
I. M.
Dayton
, T.
Sage
, E. C.
Gingrich
, M. G.
Loving
, T. F.
Ambrose
, N. P.
Siwak
, S.
Keebaugh
, C.
Kirby
, D. L.
Miller
, A. Y.
Herr
, Q. P.
Herr
, and O.
Naaman
, “Experimental demonstration of a Josephson magnetic memory cell with a programmable φ-junction
,” IEEE Magn. Lett.
9
, 1
–5
(2018
). 16.
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
, 1
(2006
). 17.
V.
Aguilar
, D.
Korucu
, J. A.
Glick
, R.
Loloee
, W. P.
Pratt
, and N. O.
Birge
, “Spin-polarized triplet supercurrent in Josephson junctions with perpendicular ferromagnetic layers
,” Phys. Rev. B
102
, 024518
(2020
). 18.
A. I.
Buzdin
, “Proximity effects in superconductor-ferromagnet heterostructures
,” Rev. Mod. Phys.
77
, 935
(2005
). 19.
J.
Linder
and J. W. A.
Robinson
, “Superconducting spintronics
,” Nat. Phys.
11
, 307
–315
(2015
). 20.
C.
Bell
, G.
Burnell
, C. W.
Leung
, E. J.
Tarte
, D.-J.
Kang
, and M. G.
Blamire
, “Controllable Josephson current through a pseudospin-valve structure
,” Appl. Phys. Lett.
84
, 1153
–1155
(2004
). 21.
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
–2430
(2001
). 22.
T.
van Duzer
and C. W.
Turner
, Principles of Superconductive Devices and Circuits
(Elsevier
, 1981
).23.
K. K.
Likharev
and V. K.
Semenov
, “RSFQ logic/memory family : A new Josephson-junction technology for digital systems
,” IEEE Trans. Appl. Supercond.
1
, 3
–28
(1991
). 24.
S. K.
Tolpygo
and V. K.
Semenov
, “Increasing integration scale of superconductor electronics beyond one million Josephson junctions
,” J. Phys.: Conf. Ser.
1559
, 012002 (2020
).25.
A.
Fischer
, R.
Kruk
, and H.
Hahn
, “A versatile apparatus for the fine-tuned synthesis of cluster-based materials
,” Rev. Sci. Instrum.
86
, 023304
(2015
). 26.
N.
Gack
, G.
Iankevich
, C.
Benel
, R.
Kruk
, D.
Wang
, H.
Hahn
, and T.
Reisinger
, “Magnetotransport properties of ferromagnetic nanoparticles in a semiconductor matrix studied by precise size-selective cluster ion beam deposition
,” Nanomaterials
10
, 2192
(2020
). 27.
V.
Ambegaokar
and B. I.
Halperin
, “Voltage due to thermal noise in the dc Josephson effect
,” Phys. Rev. Lett.
22
, 1364
–1366
(1969
). 28.
Y. M.
Ivanchenko
and L. A.
Zil’berman
, “The Josephson effect in small tunnel contacts
,” Sov. Phys. JETP
28
, 1272
(1969
).© 2022 Author(s). Published under an exclusive license by AIP Publishing.
2022
Author(s)
You do not currently have access to this content.
