Tuning the antiferromagnetic easy axis direction in exchange bias bilayers

Abstract The exchange bias effect is measured for a Co/NiO bilayer before and after it has been cooled down from 580 K in 1.5 kOe magnetic field applied at 45° to the initial exchange-bias direction. The angular variation of the hysteresis loop shift for the treated sample showed three distinct minima and maxima, in contrast to that of the as-made sample, which is characteristic for a system with aligned ferromagnetic and antiferromagnetic easy axes. This behavior is qualitatively well explained in the framework of the domain-wall formation model applied for the off-aligned case.