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) anisotropyKAFwas found. An increase in exchange biasHexwas 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 diameterDM, or in the median blocking temperature (TB), and consequentlyKAF, with the addition of Mn. However in the samples with the Mn interfacial layersHexwas found to increase by up to 100 Oe when the setting fieldHset, was varied from 5 to 20 kOe.