Field Dependence of the Remanent Magnetization in Spin Glasses

Abstract

The field dependence of the remanent magnetization of a Cu 5 at.% Mn spin glass has been investigated in both isothermal remanent magnetization (MIRM) and thermoremanent magnetization (MTRM) experiments. The measurements reveal fundamentally new features of the remanent magnetization. At low fields the MTRM(H) curves show a nonlinear field dependence due to the nonlinear behaviour of the equilibrium magnetization, whereas the MIRM(H) curves show a linear field dependence due to the linear response of the spin glass relaxation. Additional features are a pronounced maximum in the remanent magnetization not only in MTRM(H), but also in MIRM(H), and a striking wait time dependence of both MTRM(H) and MIRM(H). The results give essential implications on how to perform and interpret measurements of the time decay of MTRM(t).