Theory Of Interlayer Exchange Coupling In F/NM Multilayers Film

The coupling between two ferromagnetic layers separated by a nonferromagnetic spacer layer is mediated by the electrons of the spacer layer. The coupling oscillates in sign as a function of thickness where the DSC decrease with the reciprocal square of spacer thickness . This phenomena is related to the RKKY interaction between magnetic impurities. Theory predicts that the periods of the oscillatory coupling should depend on critical spanning vectors of the Fermi surface belonging to the spacer layer material. There is a remarkable agreement for the measured periods and those predicated from Fermi surface. The long range oscillation is believed to be related to the spin polarization of conduction electrons. There is essentially agreement between theory and experiment on the strength of the SEC The GMR has been ascribed to spin dependent scattering in the Ferromagnetic layers The RKKY theory of IEC successfully describes the IEC decays reciprocal square of nonmagnetic layer, but it failes to gives a quantitative description of the amplitude and phase of the oscillatory of the IEC. an increase of temperature led to a decrease of IEC and GMR, this can be attributed to inelastic scattering by phonon and to electron-magnon scattering, the saturation field, GMR, DEC are all decreasing with in creasing pressure. When the thickness of the nonmagnetic layer increased, the GMR decreases as the ratio of mean free path to the nonmagnetic thickness decrease and to vanish when this ratio becomes much smaller than one. The GMR ratio is much larger for multilayer structures than for simple sandwich structures, this is related to the scattering in both alternative ferromagnetic layer and alternative interface.