Atomistic origin of the athermal training effect in granular IrMn/CoFe bilayers

Anti-ferromagnetic materials have the possibility to offer ultra fast, high data density spintronic devices. A significant challenge is reliable detection of state antiferromagnet, which can be achieved using exchange bias. Here we develop an atomistic spin model athermal training effect, a well known phenomenon in biased systems where bias significantly reduced after first hysteresis cycle. We find that setting process granular thin films relies on presence interfacial mixing between ferromagnetic and antiferromagnetic layers. systematically investigate effect intermixing bias, switching field coercivity all increase with increased intermixing. The highly frustrated leading systematic decrease ordering ferromagnet. This metastable structure initially irreversible spins leads large effective coupling thus field. After cycle these drop into reversible ground repeatable for subsequent cycles, demonstrating truly athermal. Our simulations provide new insights role interface importance structures could help design optimisation