Magnetic relaxation in Zn(PO3)2·Er(PO3)3 glass

Abstract The results of experimental studies of alternating (ac) magnetic susceptibility and specific heat of Zn(PO 3 ) 2 ·Er(PO 3 ) 3 glass are reported. Despite a high concentration of magnetic Er(III) ions the analysis of ac susceptibility ruled out the formation of a spin glass state in the used range of temperatures. Two relaxation processes were identified. The first one is thermally activated with a crossover in its temperature dependence observed at nominally 7 K. The relaxation at lower temperatures seems to be governed by a direct process with pronounced effect of phonon bottleneck. Striking deceleration of spin dynamics with increasing temperature found above 7 K is tentatively attributed to overcoming Ioffe – Regel crossover and strong scattering of acoustic phonons on local modes. Simplified prediction derived from a soft-mode-dynamics model confirms the presence of the boson peak observed in specific heat data and reasonably predicts the temperature of the crossover. The second process is consistent with a cross – tunneling relaxation. The obtained results suggest that magnetic doping of glasses and studying magnetic relaxation may represent an alternative tool for the investigation of lattice modes in glasses.