Mapping motion of antiferromagnetic interfacial uncompensated magnetic moment in exchange-biased bilayers

In this work, disordered-IrMn(3)/insulating-Y(3)Fe(5)O(12) exchange-biased bilayers are studied. The behavior of the net magnetic moment Δm(AFM) in the antiferromagnet is directly probed by anomalous and planar Hall effects, and anisotropic magnetoresistance. The Δm(AFM) is proved to come from the interfacial uncompensated magnetic moment. We demonstrate that the exchange bias and rotational hysteresis loss are induced by partial rotation and irreversible switching of the Δm(AFM). In the athermal training effect, the state of the Δm(AFM) cannot be recovered after one cycle of hysteresis loop. This work highlights the fundamental role of the Δm(AFM) in the exchange bias and facilitates the manipulation of antiferromagnetic spintronic devices.