Identification and separation of two distinct contributions to the training effect in polycrystalline Co/FeMn bilayers

We show that polycrystalline Co/FeMn bilayers display two distinct forms of training effect. The two can be identified and separated via their distinctive field cycle and antiferromagnet thickness dependences, in addition to their influence on the magnetization reversal. One mode is due to the biaxial anisotropy of the antiferromagnet and leads to an abrupt single cycle training (as seen in recent modeling), while the other is a gradual effect related to depinning of uncompensated antiferromagnet spins.