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The process of magnetization reversal of a FeNi(50Å)∕FeMn(50Å) polycrystalline film prepared in a magnetic field has been investigated at temperatures ranging from 25to300K. The external field was oriented in the film plane along the easy or difficult axis of the ferromagnetic layer. In the process of magnetization reversal of the film along the easy axis, strong asymmetry of the hysteresis loop is observed together with an exchange shift. As temperature decreases, the asymmetry becomes more pronounced and the shift increases. The field dependences of the magnetization of the film are symmetric and are not shifted when the external field is applied along the difficult axis. The magnetization reversal process is examined on the basis of a model that takes account of the appearance of high-order exchange anisotropy in polycrystalline films. It is shown that the observed strong asymmetry of the hysteresis loop is associated with the formation of a canted phase and the existence of a metastable state. As the film temperature decreases, the interval of fields where the canted phase can exist becomes wider as a result of an increase of the exchange anisotropy constants.

Magnetization reversal processes in ferrimagnetically ordered Co/Gd multilayers were studied by means of the magneto-optical Kerr effect. Temperature dependencies of coercive field of the multilayers have been determined in the wide temperature region 25<T<300 K. An increase of temperature can cause both an enhancement and diminution of coercivity in the Co/Gd multilayers examined. Different temperature behavior of coercivity is explained by taking into account the temperature variation of net magnetization in the ferrimagnetically ordered Co/Gd multilayers.