Ferromagnetic-spin glass transition

Elastic and inelastic neutron scattering studies were performed on the amorphous alloy (Fe77Cr23)75P16B6Al3. These measurements were conducted over a temperature range from 1.8 K to room temperature. The elastic scattering results obtained at Q = 0.025A-1 indicated a Curie temperature of 1850K in addition to a ferromagnetic-spin glass transition below 20 K. These values are consistent with the phase diagram construction resulting from the magnetization and ac susceptibility measurements of Yeshurun et al. Inelastic neutron scattering measurements resulted in well-defined spin waves being observed in the ferromagnetic phase. For the small Q range studied (0.05A-1 to 0.1A-1), the spin wave energies followed a quadratic dispersion. As the temperature was lowered towards the spin glass regime, the spin wave energies decreased indicating a softening of the magnetic stiffness constant. Below 100K, no well-defined spin wave excitations were present; however, a quasielastic peak, which increased slightly as the temperature was lowered, was observed