Independence of spin-orbit torques from the exchange bias direction in Ni${}_{81}$Fe${}_{19}$/IrMn bilayers

Abstract

We investigated a possible correlation between spin Hall angles and exchange bias in Ni${}_{81}$Fe${}_{19}$/IrMn samples by performing spin torque ferromagnetic resonance measurements. This correlation is probed by patterning of Ni${}_{81}$Fe${}_{19}$/IrMn bilayers in different relative orientations with respect to the exchange bias direction. The measured voltage spectra allow a quantitative determination of spin Hall angles, which are independent of the orientation around 2.8\pm0.3%.

10 pages