Optimizing supercurrent transmission in NiFe ferromagnetic Josephson junctions using Ni “dusting”*

Josephson junctions with ferromagnetic layers where the ground-state phase difference can be reliably controlled are a potential candidate for applications in cryogenic memory devices, which can greatly reduce the ever-growing energy requirements for large-scale computing. Phase control has been successfully demonstrated with junctions containing a Ni fixed layer and a NiFe free layer [1,2]. However, there are still several improvements that can be made to increase the efficiency and reliability of these junctions. We present work on improving the transmission efficiency of single layer NiFe junctions by “dusting” the NiFe with thin layers of Ni on both sides. We also present a study of the 0-Pi transitions in these Ni “dusted” NiFe junctions.
[1] E. C. Gingrich, B. M. Niedzielski, J. A. Glick, Y. Wang, D. L. Miller, R. Loloee, W. P. Pratt, and N. O. Birge, Nat. Phys. 12, 564 (2016).
[2] I. Dayton, T. Sage, E. Gingrich, M. Loving, T. Ambrose, N. Siwak, S. Keebaugh, C. Kirby, D. Miller, A. Herr, Q. Herr, and O. Naaman, IEEE Magn. Lett. 9, 3301905 (2018).