Exchange Coupling in NiFe/NiMn Bilayer And Properties of NiMn-pinned Spin Valve

抄録

The effects of annealing on the exchange coupling in NiFe/NiMn bilayers and the properties of NiMn-pinned spin valve are studied. With increasing annealing time and annealing temperature, the exchange coupling field H_ex first increases, followed by a decrease. The evolution of H_ex with annealing is the competing result between nonmagnetic fcc-antiferromagnetic fct phase transition and interfacial diffusion. The exchange coupling between NiFe and NiMn layers is very stable at temperatures from room temperature to about 210 °C. The distribution of blocking temperature T_b is responsible for the thermal stability. For the NiMn-pinned spin valve, a lower annealing temperature is favorable, at the expense of a longer time to obtain a desired exchange coupling field.