Ag layer thickness dependence of magnetic properties in Fe/Ag superlattices

The magnetic properties of [Fe(20Å)/Ag(t)]20 superlattices with Ag film thickness varying from 7 to 20Å, prepared by molecular beam epitaxy on (001)MgO substrate, are presented. The epitaxial growth and the quality of layered structure of the samples were controlled by RHEED and X-ray diffraction techniques. Magnetic hysteresis loops with the magnetic field applied parallel and perpendicular to the plane of the films were determined by vibrating sample magnetometer and superconducting quantum interference device (SQUID) magnetometer at 4.2K. Magnetotransport properties were measured by conventional DC four terminal method with the magnetic field applied parallel to the plane of the films at 4.2K. The analysis of the hysteresis loops indicates an in plane easy magnetization axis and shows a dependence of the interface anisotropy on the Ag film thickness.