Magnetic behavior of ferromagnets with random anisotropy

This article reports on a magnetometric study of the effects of diluted local random anisotropy in a ferromagnetic FegoB20 amorphous matrix. In the low-temperature and low-field regime the samples, Fe74RE6B20 (RE = Nd, Ce), show a very rich behavior as a consequence of the competition between, and different dependence on T, of the correlation length associated with local random anisotropy and exchange interactions. In the high-field regime (Happlied? 1.5 kOe) we observe ferromagnetic behavior with the saturation magnetization varying with temperature according to Bloch's law, The spin wave stiffness constant D could be determined and lies close to 100 meV..4. •