Long relaxation phenomena studied by measurements of dynamic susceptibility in a weak random anisotropy magnet

Abstract

Abstract We investigated characteristic dynamical properties of a weak random anisotropy magnet by measuring AC susceptibility χ * ( ω ) of a-Ho 28 Fe 72 thin film: (i) the imaginary part (Im χ ) of χ * ( ω ) is larger than the real part (Re χ ) at measuring frequency range (from 35 Hz to 1.4 kHz) at around the transition temperature T c , (ii) a “dip” in Re χ at about T c in the frequency range higher than 870 Hz is observed, which suggests a critical relaxation and (iii) by using the Cole–Cole analysis, it is found that the distribution of relaxation time broadens drastically around T c .