The thermal stability of the MR ratio in spin-valve films using FeMn, CrMnPt, and MnIr antiferromagnetic films was investigated. The decrease in the MR ratio caused by annealing was significantly reduced by using a thick pinned layer and a thin antiferromagnetic film. The thermal stability of the MR ratio also depends on the noble metal content of an antiferromagnetic film. X-ray diffraction profiles of the spin-valve films using FeMn films showed an increase in the (111) peak intensity after annealing, and the intensity change was closely related to the thermal stability of the MR ratio. It is obvious that thermal treatment causes a strong interaction between a pinned layer and an antiferromagnetic film.
