Crystallization and hyperfine fields in Fe-Hf based amorphous alloys

Abstract

The magnetic properties and crystallization have been investigated in the amorphous ferromagnets Fe_80−xHf_xB₁₂Si₅Al₃ (0≤x≤9). The Fe hyperfine field and Fe magnetic moment were found to be 285 kOe and 1.51 μ_B, respectively, in Fe₈₀B₁₂Si₅Al₃. These quantities were found to decrease with increasing x by 9 kOe per atomic percent and 0.063 μ_B per atomic percent, respectively. The ratio of the Fe field to the Fe moment, however, was found to be essentially independent of x at 180 kOe/μ_B. A thermal analysis measurement of the alloy Fe₈₀B₁₂Si₅Al₃ showed two crystallization peaks: one at 730 and the other at 804 K. Both of these increase in temperature as Hf is added to the system. For x≥3, additional crystallization process peaks were observed which are presumably due to the crystallization of Fe–Hf phases.