  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.
