Protected 0-π states in SIsFS junctions for Josephson memory and logic

Applied Physics Letters. 2018. Vol. 113. No. 082602. P. 082602-1–082602-5.

Bakurskiy S. V., Klenov N. V., Soloviev I. I., Pugach N., Kupriyanov M. Y., Golubov A. A.

We study the peculiarities in current-phase relations (CPR) of the SIsFS junction in the region of 0
to p transition. These CPR consist of two independent branches corresponding to 0- and p-states of
the contact. We have found that depending on the transparency of the SIs tunnel barrier, the decrease
in the s-layer thickness leads to transformation of the CPR shape going in the two possible ways:
either one of the branches exists only in discrete intervals of the phase difference u or both branches
are sinusoidal but differ in the magnitude of their critical currents. We demonstrate that the difference
can be as large as 10% under maintaining superconductivity in the s layer. An applicability of
these phenomena for memory and logic application is discussed.

Keywords: сверхпроводник-феррромагнетик, superconductor/ferromagnet heterostructures