Polarized current changes the exchange bias in a current-in-plane spin valve

A spin-polarized current changes the strength and direction of the exchange bias in spin valves with a current-in-plane geometry. The exchange bias can be manipulated and systematically changed by applying current pulses. The changes are nonmonotonic and asymmetric with respect to the directions of the applied field and current pulses. For different current pulses, different exchange-bias fields can be achieved in the same sample. Furthermore, for samples with different exchange bias, the bias field exhibits a dependence on the applied pulse. Since the strength of exchange bias is highly correlated to the micromagnetic state distribution of the antiferromagnet, we explain our observations by the spin torque exerted on the interfacial antiferromagnetic moments, excluding Joule heating and training effects. (c) 2008 Elsevier B. V. All rights reserved.