2014/10/16 by Burm Baek, William H. Rippard, Matthew R. Pufall +4
Physics and Astronomy · #cond-mat.supr-con
published as Phys. Rev. Appl. 3 (2015) 011001
arxiv created 2014/10/16 · arxiv updated 2015/01/22
The combination of superconducting and magnetic materials to create novel superconducting devices has been motivated by the discovery of Josephson critical current (Ics) oscillations as a function of magnetic layer thickness and the demonstration of devices with switchable critical currents. However, none of the hybrid devices have shown any spintronic effects, such as spin-transfer torque, which are currently used in room-temperature magnetic devices, including spin-transfer torque random-access memory and spin-torque nano-oscillators. We have developed nanopillar Josephson junctions with a minimum feature size of 50 nm and magnetic barriers exhibiting magnetic pseudo-spin-valve behavior at 4 K. These devices allow current-induced magnetization switching that results in 20-fold changes in Ics. The current-induced magnetic switching is consistent with spin-transfer torque models for room-temperature magnetic devices. Our work demonstrates that devices that combine superconducting and spintronic functions show promise for the development of a nanoscale, nonvolatile, cryogenic memory technology.