Observation of Cluster Glass and Griffiths‐like Phase in Fe3O4 Nanostructures

Abstract

In the present investigation, the rare occurrence of Griffiths-like phase (GP) in Fe3O4 (magnetite) nanostructures is observed for the first time. Initially, Fe3O4 monodispersed nanoparticles and an intercalated ensemble of nanoparticles and nanorods are successfully synthesized by a facile one-step synthesis. The magnetization, as a function of the applied field, confirms the absence of superparamagnetism in both samples. The thermomagnetic data at cryogenic temperatures show glassy nature, and the alternating current (AC) susceptibility measurements confirm the existence of cluster glass. The low-field direct current (DC) magnetization measurements of Fe3O4 nanostructures show an anomalous magnetic behavior, which indicates the presence of GP above its Curie temperature. This unusual behavior is attributed to the presence of short-range magnetic correlations and ferromagnetic clusters present in the system due to the size reduction.