Critical Behaviour of Spin Relaxation in EuS

Abstract

We have measured both real and imaginary part of magnetic susceptibility of EuS near the Curie temperature T_c by means of the high frequency magnetic susceptibility measurement method, in which no demagnetization corrections have been required. Except for the immediate vicinity of T_c, the critical relaxation spectra obtained are described by a Debye form of relaxation and the critical index of the relaxation time is determined to be Δ=1.26±0.03. The value of Δ is slightly smaller than that of the static susceptibility, γ=1.41±0.01. For temperatures closer to T_c, the critical relaxation spectra become to exhibit a polydispersive character.