  The microscopic magnetic properties of high-quality GdN thin films have been
investigated by electron spin resonance (ESR) and ferromagnetic resonance (FMR)
measurements. Detailed temperature dependence ESR measurements have shown the
existence of two ferromagnetic components at lower temperatures which was not
clear from the previous magnetization measurements. The temperature, where the
resonance shift occurs for the major ferromagnetic component, seems to be
consistent with the Curie temperature obtained from the previous magnetization
measurement. On the other hand, the divergence of line width is observed around
57 K for the minor ferromagnetic component. The magnetic anisotropies of GdN
thin films have been obtained by the analysis of FMR angular dependence
observed at 4.2 K. Combining the X-ray diffraction results, the correlation
between the magnetic anisotropies and the lattice constants is discussed.
