Relaxation phenomena in SSG Fe3O4 nanoparticle system

Abstract

Fe3O4 nanoparticles were synthesized by thermal decomposition of organic precursor (acac complex) and the structural characterization was done by TEM measurements. In order to understand magnetic behavior of the examined Fe3O4 system magnetic characterization was done by SQIUD measurements in AC and DC regime. Sample exerts memory effects and aging phenomena, all pointing to the existence of super spin glass state at low temperatures. Appropriate interpretation of the measured effects can be provided within the framework of droplet and hierarchical models. Investigation of relaxation phenomena comprised measurements of zero field cooled and thermoremanent magnetization time decay. Time dependence of the related relaxation rates showed unusual trend of slowing down with increasing temperature. The origin of observed behavior still remains an open question.