Magnetic properties of ultrathin Ni films

The magnetic properties of Au/Ni/Si(100) films with Ni thicknesses of 8–200 A are studied at T=77 K using a scanning magnetic microscope with a thin-film high-temperature dc SQUID. It is found that the Ni films, with an area of 0.6×0.6 mm, which are thicker than 26 A have a single-domain structure with the magnetic moment oriented in the plane of the film and a saturation magnetization close to 0.17 MA/m. For films less than 26 A thick, the magnetization of the film is found to drop sharply.