Thermal variation in magnetic-properties of laser annealed ga-substituted euyig films

Abstract

Laser annealing makes available substituted bubble garnet films with identical composition but widely differing cation distributions. To investigate the thermal dependence of the magnetic properties of these films, we developed a high temperature bubble statics technique (293 to 440K), and employed variable temperature SQUID magnetometry (4.3 to 400K) and ferromagnetic resonance (~7.5 to 293K). We have studied the variation of saturation magnetization (4‘lTMs) and the uniaxial anisotropy constant (Ku) in laser-annealed, substituted EuY ig films from approximately 50K to each sample's Curie temperature (Tc), In films (with identical composition) whose room temperature magnetizations vary by nearly 2: 1, we find thermal dependencies for 4πMs that support the simple cation exchange model for laser annealing. The temperature dependence of Kuis remarkably linear from 100K (below saturation of 4πMs) to about 50° below Tc - in each sample, indicating a significant magnetostrictive contribution. Temperature stabilities of 4 πMs and Q are also discussed. © 1983 IEEE