Magnetoelasticity and internal friction of an amorphous ferromagnetic alloy

Abstract

The magnetomechanical behavior of the splat‐cooled amorphous alloy Fe₇₅P₁₅C₁₀ has been studied at audio frequencies by a vibrating‐reed technique. The ΔE effect exhibits a maximum value at a magnetization near 0.5M_S. 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.