Spin-wave excitations and low-temperature magnetization in the amorphous metallic ferromagnetic (Fe/sub x/Ni/sub 1-x/)/sub 75/P/sub 16/B/sub 6/Al/sub 3/
We have carried out a systematic study of the spin-wave dispersion relations and the low-temperature magnetization in the amorphous metallic ferromagnets (Fe/sub x/Ni/sub 1-x/)/sub 75/P/sub 16/B/sub 6/Al/sub 3/ for x = 1.0, 0.65, 0.5, and 0.30. In this series the Ni is, to a first approximation, nonmagnetic. The spin-wave measurements were carried out using inelastic-neutron-scattering techniques, the magnetization at finite fields (1.2 and 15 kOe) was measured via a vibrating-sample magnetometer and the temperature dependence of the magnetization at zero field was deduced from the hyperfine field at the Fe sites as measured by Moessbauer techniques. The spin waves follow a normal ferromagnetic dispersion relation, h ..omega.. (q) = ..delta.. + Dq/sup 2/ + Eq/sup 4/ + ..., in all materials. The magnetization follows the law M (T) = M/sub o/(1 - BT/sup 3/2/ - ...). The T/sup 3/2/ coefficient B is nearly field independent for the samples with x = 1.0, 0.65, and 0.5. Further the Moessbauer and magnetometer measurements are in close quantitative agreement. We find that for these samples the observed B's are properly accounted for by the measured spin-wave dispersion relations in contrast to previous studies in other magnetic glasses. Anomalous effects are observed in the x = 0.30 sample.
- Research Organization:
- Department of Physics and Center for Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
- OSTI ID:
- 6935470
- Journal Information:
- Phys. Rev., B; (United States), Journal Name: Phys. Rev., B; (United States) Vol. 18:5; ISSN PLRBA
- Country of Publication:
- United States
- Language:
- English
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