The mechanisms played by Ag as a surfactant in giant magnetoresistance multilayers were investigated using interface sensitive x-ray anomalous scattering techniques. Analysis on [Cu∕Ni70Co30]20 and [Cu∕Ag∕Ni70Co30]20 multilayers revealed that 6Å thick NiCu and 6Å thick CuNi3Co intermixing regions are formed at the Ni70Co30-on-Cu interfaces of undoped and Ag-doped multilayers, respectively. The Cu-on-Ni70Co30 interfaces in both multilayers are sharp. Annealing causes severe diffusion across both types of interfaces in the undoped multilayer. But the interfaces in the Ag-doped multilayer do not change significantly upon annealing, except that Ag atoms diffuse into the whole Ni70Co30 layer and some parts of the Cu layer. The results suggest that addition of Ag during the deposition suppresses interfacial intermixing. X-ray diffuse scattering profiles show that the interfacial lateral correlation length of the Ag-doped multilayer is longer than that of the undoped multilayer and does not change significantly after annealing, suggesting that the addition of Ag gives rise to smoother interfaces and results in a good thermal stability.

The exchange biasing of Co0.9Fe0.1 film by the antiferromagnet Ir–Mn via a thin intermediate Co0.6Fe0.4 layer was investigated. It has been found that the exchange bias is drastically enhanced with the insertion of an ultra-thin Co0.6Fe0.4 layer at the interface between Co0.9Fe0.1 and Ir–Mn layers. For the Ir0.25Mn0.75(100 Å)/Co0.9Fe0.1(150 Å) bilayer, the pinning field at room temperature is raised from 92 to 206 Oe when a 4 Å Co0.6Fe0.4 layer is introduced at the interface, and further enhanced to 262 Oe with a 10 Å Co0.6Fe0.4 insertion layer. The corresponding unidirectional anisotropy increases from 0.18 to 0.4 erg cm−2 and reaches a value of 0.54 erg cm−2. The extra large unidirectional anisotropy is maintained as the Co0.6Fe0.4 thickness exceeds 10 Å. The high blocking temperature of the Ir–Mn/Co0.9Fe0.1 bilayer is unaffected by the insertion of the Co0.6Fe0.4 layer. The present results indicate that exchange bias is essentially determined by interfacial spins and, most importantly, the performance of the exchange bias system Ir–Mn/Co0.9Fe0.1, which is commonly used in spin valve giant magnetoresistance devices, can be greatly promoted by the insertion of an ultra-thin interfacial Co0.6Fe0.4 layer.

The thickness dependence of microstructures of La 0.8 Ca 0.2 MnO 3 ͑LCMO͒ / SrTiO 3 ͑STO͒ thin films was investigated by high-resolution x-ray diffraction, small angle x-ray reflection, grazing incidence x-ray diffraction, scanning electron microscopy, and atomic force microscopy. The results show that all the LCMO films are well oriented in ͑00l͒ direction perpendicular to the substrate surface. Self-organized crystalline grains with a tetragonal shape are uniformly distributed on the film surface, indicating the deposition condition being of benefit to the formation of the crystalline grains. With increasing the film thickness, the crystalline quality of the LCMO film is improved, while the surface becomes rougher. There exists a nondesigned cap layer on the upper surface of the LCMO layer for all the samples. The mechanism is discussed briefly.