Phase-controllable spin-triplet Josephson junctions containing a synthetic antiferromagnet

We present the first experimental demonstration of phase-controllable Josephson junctions (JJs) that carry long-range spin-triplet supercurrent. Phase-sensitive detection was achieved by measuring the interference between two such JJs in a Superconducting QUantum Interference Device (SQUID) loop. Spin-triplet supercurrent in the JJs is generated through the use of three ferromagnetic layers with noncolinear magnetizations [1]. The central layer is a synthetic antiferromagnet with magnetization perpendicular to the plane, while the other two ferromagnetic layers have in-plane magnetization, as recently demonstrated [2]. We show that the phase-state of the JJs can be switched between 0 and π over a thousand times without error, opening possibilities for their use in superconducting memory.

[1] Houzet, M. and Buzdin A. I., Phys. Rev. B 76, 060504(R) (2007).
[2] Glick J. A., et. al., arXiv: 1710.07247, (2017).