Magneto-transport and magneto-dielectric anomalies in Co doped iron oxide thin films - Microwave assisted sol-gel route

Use of microwave (MW) energy as an alternate to high temperature treatment during material synthesis is gaining much attention as it offers the advantages of being faster and econom-ical than other heating methods. A comprehensive study of structure, magnetization, and polariza-tion behaviour of Cobalt (Co) doped Fe3O4 thin films, prepared by means of microwave assisted sol-gel method is performed. Co doped (0-10 wt%) sols are prepared after irradiating them at MW power of 1000 W. Phase analysis is confirmed using XRD where Fe3O4 phase persisted with Co concentrations of 0-6 wt%. Higher concentration results in the appearance of cobalt oxide phase. Magnetic and transport properties are strongly affected by the presence of Co ions. Co doped Fe3O4 films show anisotropic behaviour with high saturation magnetization obtained for 6 wt% Co doped Fe3O4 thin films, i.e. ti 125 emu/g. Verwey transition is observed for thin films with low dopant concentration while no sharp transition in magnetization behaviour is observed for higher dopant concentration. High frequency anomaly in dielectric analysis is observed at high frequencies for Co doped Fe3O4 thin films. Negative values of magneto-dielectric coefficient show coupling of magnetic and dielectric behaviour at room temperature.(c) 2023 The Authors. Published by Elsevier B.V. on behalf of King Saud University. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

Automated summary

The use of microwave energy instead of high temperature treatment in material synthesis is becoming popular due to its advantages in terms of speed and economy. In this study, Co-doped Fe3O4 thin films were prepared using a microwave assisted sol-gel method, and their structure, magnetization, and polarization behavior were comprehensively studied. The presence of Co ions strongly affected the magnetic and transport properties of the films. The anisotropic behavior was observed in Co-doped Fe3O4 films, with the highest saturation magnetization obtained for 6 wt% Co-doped films. Verwey transition was observed at low dopant concentration, while no sharp transition in magnetization behavior was observed at higher dopant concentration. Anomalous dielectric behavior was observed at high frequencies, and negative values of the magneto-dielectric coefficient indicated the coupling of magnetic and dielectric behavior at room temperature.