MAGNETIC-PROPERTIES OF ULTRATHIN NI/CU(100) FILMS DETERMINED BY A UHV-FMR STUDY

We have performed temperature dependent ferromagnetic resonance (FMR) measurements in ultrahigh vacuum on ultrathin Ni films, epitaxially grown on Cu(100). The thickness dependence of anisotropy fields has been determined from measurements with parallel and perpendicular field orientation. Separating the resulting anisotropy constants in volume and surface contributions, we get K(eff)v almost-equal-to 3.5(7) X 10(6) erg/cm3 and K(eff)s almost-equal-to -0.17(3) erg/cm2. K(eff)v is explained within a model of homogeneous strain due to pseudomorphic growth below 7 ML. In addition very small FMR linewidths of approximately 200 G have been observed, indicating that the films consist of large magnetic homogeneous domains. The increase of the linewidth at the phase transition allows us to determine the Curie temperature, whose thickness dependence is explained by a finite size scaling law.