Magnetic anisotropy in IrMn/Co structures with an alternative sequence of deposition of antiferromagnetic and ferromagnetic layers

The preparation conditions and the magnitudes of the uniaxial and unidirectional magnetic anisotropies of IrMn/Co structures with an alternative sequence of deposition of antiferromagnetic and ferromagnetic layers upon heat treatment and cooling in an external magnetic field have been investigated. It has been revealed that the unidirectional anisotropy (exchange bias) arises in the structure with an antiferromagnetic layer deposited on a ferromagnetic layer (TS structure) at an annealing temperature of higher than 100°C. In structures with a ferromagnetic layer deposited on an antiferromagnetic layer (BS structure), the exchange bias does not arise in the annealing temperature range under investigation. The possible factors responsible for this effect and the ratio between the temperature of the appearance of the exchange bias and the Neel temperature have been discussed.