STATIC AND DYNAMIC-RESPONSE OF CLUSTER GLASS IN LA0.5SR0.5COO3

The static and dynamic response of cluster glass in La0.5Sr0.5CoO3 has been experimentally investigated through linear and nonlinear ac susc eptibility measurements in the frequency range 137 Hz to 1370 Hz; ac f ield (1-10 Oe), dc field (0-40 Oe). Field cooled and zero field cooled de magnetization data have also been reported. An attempt has been ma de to compare the dynamic response of cluster glass with spin glass, r eentrant spin glass, and canted spin systems. The interesting observat ion is that in the cluster glass system, the coercivity at low fields under the zero field cooled condition does not increase rapidly, as on e approaches the so-called freezing temperature (T-f), unlike that in typical reentrant spin glass systems. We also observed a linear relati on of field cooled coercivity, H-c(FC) (i.e., the coercive force to br ing the thermoremanent magnetization to zero) with cooling fields (H-F C) at different temperatures. The variation of dH(c)(FC)/dH(FC) with T (K) shows an exponential behavior for T less than or equal to T-c. We believe that this is a significant observation for cluster glass syste ms.