An ac susceptibility study of spin dynamics in a super spin glass nanoparticle La0.7Ca0.3MnO3 system: simultaneous relaxation processes

In this paper, we present the results of a systematic study of nonequilibrium dynamics in a strongly interacting super spin glass (SSG) nanoparticle La0.7Ca0.3MnO3 system by alternating current (ac) susceptibility measurements. Cole-Cole analysis of the obtained data revealed the simultaneous existence of two separated relaxation processes, which can be assigned to the relaxation of different magnetic entities. Along with the expected relaxation of the collective SSG phase, the existence of individual, nonagglomerated particles, which do not take part in the collective phase and relax independently, was proposed. A full dynamical scaling analysis was performed in order to elucidate the nature of the transition to a low-temperature SSG state in the interacting La0.7Ca0.3MnO3 nanoparticle sample.