Spin-glass dynamics of La_0.95Sr_0.05CoO₃

Experimental studies of dynamic magnetic properties of a highly homogeneous sample of La_0.95Sr_0.05CoO₃ perovskite evidence the existence of a low-temperature spin-glass phase. A dynamic scaling analysis of ac susceptibility data according to conventional critical slowing down implies a finite spin-glass phase-transition temperature T_g≈14.6K and a dynamic exponent zν≈10.3. Low-field magnetic relaxation experiments show essentially logarithmic magnetic relaxation and aging effects at all temperatures below T_g and that temperature perturbations affect the relaxation function in a way that is characteristic for a low-temperature spin-glass phase. Finally, it is also shown that “simple” remanent magnetization vs temperature curves, measured after specific cooling protocols, can yield information on dynamic properties such as aging and memory phenomena.