The distribution of magnetic moments and the temperature dependence of reduced hyperfine fields in amorphous ferromagnets

The distribution of magnetic moments in amorphous transition metal-metalloid ferromagnetic alloys is first estimated from the linewidths of hyperfine fields. The result shows that there exists a rather broad distribution of magnetic moments with some spins aligned antiferromagnetically in the alloys. The temperature dependence of reduced hyperfine fields in the alloys is evaluated by a simple molecular-field theory, taking account of the distribution of magnetic moments in addition to the usual exchange fluctuations. Quantitative agreement between the theoretical and experimental curves is more rectified at the intermediate reduced temperature range, in comparison with the case of the usual exchange fluctuations. (author)