Interface Effects in Tri-layer IrMn Exchange Biased Systems

This work investigates interface and annealing effects in tri-layer IrMn exchange biased systems. Two samples have been studied with the same initial structure of Si\SiO2\NiCr(5 nm)\CoFe(12 nm)\IrMn(5 nm): Sample A had CoFe (8 nm) and sample B hadNiFe (10 nm). There was also an additional NiCr(5 nm) capping layer to prevent corrosion. The different thicknesses of the top layer and bottom layers of the tri-layer stack enables identification of each layer on the hysteresis loop. Samples were measured as prepared and after annealing at 200, 250 and 300degC for 4 hours in a saturating field of 1 kOe. This paper also discusses the separate effects of the interface and particularly the grain size distribution in the antiferromagnetic layer on both the exchange bias and coercivity.