Linear and nonlinear AC susceptibility studies in La(Mn1−xCux)O3

The linear and nonlinear AC susceptibility as a function of temperature were measured on LaMn1−xCuxO3 compounds for x=0.05-0.30. Samples with x⩾0.10 exhibit paramagnetic to ferromagnetic transitions followed by low temperature spin glass like transition. The linear susceptibility exhibits strong frequency dependence and is analyzed in terms of standard theoretical model for spin glass. The magnitude and peak temperature of nonlinear susceptibility vary with AC field amplitudes. They are analyzed in terms of critical behaviour in the vicinity of spin glass transition temperature and the critical exponent is found to be 3.2.