Tsuneharu Takeda

Annealing temperature dependence of TC of thin‐film Gd grown on a glass substrate

Thin films of Gd were grown on a glass substrate with a sputtering technique. Measurements of x‐ray diffraction, magnetization, and electrical resistance were carried out for different samples that were annealed at various temperatures after the deposition. The deposited films are polycrystalline of hcp structure with preferred orientation, with the (100) plane parallel to the sample surface. The estimated Curie temperature TC of these films changes between 273 and 293 K, depending on the annealing temperature. It is found that this variation of TC is correlated with the relaxation of lattice imperfections.

Thin-Film Gd 4 Bi 3 Grown on a Glass Substrate

Sputtered thin-films of Gd-Bi (4:3 in atomic ratio) were annealed in vacuum under various annealing conditions. The samples annealed at a temperature near 530°C and 4 hours contained 40% of poly-crystalline Gd 4 Bi 3 phase, which is of the anti-Th 3 P 4 structure. The main peak in the x-ray diffraction spectrum due to Gd 4 Bi 3 is of (310). The phase of Gd 4 Bi 3 was not found for a lower annealing temperature; for a higher annealing temperature (above 550°C), this phase could not be observed, because other phases or structures were beginning to grow, e. g. Gd 5 Bi 3 and/or GdBi phases. The Curie temperature of the Gd 4 Bi 3 thin-films was estimated to be about 330 K; this value is nearly the same as that of bulk Gd 4 Bi 3 . The residual resistance of the Gd 4 Bi 3 thin-films was several times as large as that of bulk Gd 4 Bi 3 poly-crystal.