Effect of Mn Interface Doping in Polycrystalline Exchange Bias Thin Films

We report on the effect of 0–5 monoatomic layers of Mn deposited at the interface of a CoFe/IrMn polycrystalline thin film. All samples were produced via sputtering. Thermal activation measurements were carried out using the well-established York Protocols. In conjunction with grain size analysis performed on each sample the value of the antiferromagnet (AF) anisotropy
${K}_{{\rm AF}}$
was found. An increase in exchange bias
${H}_{{\rm ex}}$
was found in the case of 1–2 atomic layers, however a sharp decrease was seen with the addition of further layers. There was no change in the median grain diameter
${D}_{{M}}$
, or in the median blocking temperature
$\langle {T}_{B} \rangle$
, and consequently
${K}_{{\rm AF}}$
, with the addition of Mn. However in the samples with the Mn interfacial layers
${H}_{{\rm ex}}$
was found to increase by up to 100 Oe when the setting field
${H}_{{\rm set}}$
, was varied from 5 to 20 kOe.