Magnetoelasticity and internal friction of an amorphous ferromagnetic alloy

Abstract

The magnetomechanical behavior of the splat-cooled amorphous alloy Fe 75P15C10 has been studied at audio frequencies by a vibrating-reed technique. The ΔE effect exhibits a maximum value at a magnetization near 0.5MS. Such a maximum has only rarely been observed in the past, but now appears to be a general feature of the complete or fully relaxed ΔE effect exhibited in the absence of eddy-current shielding. Attention is drawn to the separation of the ΔE effect into macroscopic, microscopic, and hysteretic contributions, to complement a similar categorization of the internal friction behavior. The ΔE effect of the amorphous alloy can be enhanced to large values (ΔE/E=0.4) by thermal annealing, a behavior attributed to the relief of internal stress and the absence of a strong structural anisotropy. Internal friction measurements made as a function of magnetization, strain amplitude, and frequency reveal the existence of an extra magnetomechanical loss beyond that accounted for by eddy-current damping and Rayleigh-type magnetomechanical hysteresis.