Frustration-Induced Relaxation in Polycrystalline Nd1- xSrxCoO3 (x=0.10, 0.15, 0.20)

Abstract

This paper attempts to examine the details on the magnetic relaxation and aging effect of cobaltite Nd_{1- x}Sr_xCoO₃ (x=0.10, 0.15, 0.20). To this end, a series of polycrystalline Nd_1-xSr_xCoO₃ samples were prepared in the traditional way, and their properties were investigated from the DC magnetization, relaxation and aging effect. The field-cooled and zero-field-cooled test curves were in obvious mirror symmetry, an evidence of the disorder and frustration in the system. This situation obeys the extended exponential relationship at low temperature for Nd_1-xSr_xCoO₃. Based on the relaxation rate W (t), the author confirmed that the spin glass state is the coexistence of the spin glass and the ferromagnetic cluster. In other words, the system is spontaneously separated into the ferromagnetic cluster, the spin glass and the non-magnetic base. In addition, the relaxation and aging effect were inherent properties of the system, and the results of the interaction of ferromagnetic clusters and spin glass at the low temperature. Therefore, in Nd_1-xSr_xCoO₃ system, the spin glass behavior was determined by ferromagnetic interaction and spin glass phase; the magnetic relaxation and aging effect of Nd_1-xSr_xCoO₃ system originate from the magnetic structure of the system.