Gruppo di Fisica Statistica

The effects of the substrate and thickness on the magnetic properties of Ni thin films were investigated. Series of Ni thin films were prepared by dc diode sputtering on four different substrates: glass, Si(111), Si(100) and mica; the Ni thickness ranged from about 295 Å to 3080 Å. By X-ray diffraction, we observed that Ni grown on glass has no texture. On the other hand Ni deposited on Si gets the <111> preferred orientation for all samples. Kerr effect experiments were done using light of wavelength λ = 6328 Å and a magnetic field varying from 0 to 7 kOe. Longitudinal and polar Kerr effect measurements were performed on these samples. Kerr rotation Î?k and coercivity Hc were deduced from the hysteresis curves. These parameters were studied as a function of the substrate, the film thickness, the grain size and the texture. The experimental results are interpreted and discussed.