Magnetic and structural features of amorphous FeMo-based alloys

NANOPERM-type FeMoCuB alloys are studied using magnetic and Mössbauer measurements in the as-prepared amorphous state. It is shown that the Fe₇₆Mo₈Cu₁B₁₅ (A) and Fe₇₄Mo₈Cu₁B₁₇ (B) alloys exhibit the magnetic dipole and electrical quadrupole interactions well detected in the room-temperature Mössbauer spectra. The thermomagnetic measurements above the room temperature indicate a vanishing of the magnetic interactions at approximately 310 K (A) and at 340 K (B), respectively. The low-temperature DC magnetic measurements show an anomaly around 200 K which is also a boundary at which zero-field Mössbauer measurements of both samples reflect the gradual “vanishing” of the electrical quadrupole interactions and appearance of another magnetically ordered component. The Mössbauer measurements in the field of 4 MA/m yield a survival of quadrupole and an enhancement of magnetic dipole interactions.