Materials Science & Engineering

Biography

Biography: P.K Shishodia

Abstract

Magnetism in transition metal (TM) doped ZnO thin films and bulk has been a continued interesting area for research because it has the possibility of being dilute magnetic semiconductor with a Curie temperature near or above room temperature. Studies of doping of ZnO with metals like Mn, Co, Ni, Fe, Cr etc. have an inherent problem whether observed ferromagnetism is an intrinsic property or it is the effect of clustering of the magnetic dopant. Some of recent theoretical and experimental works have predicted that ZnO doped with TM, can exhibit ferromagnetism at or above room temperature. In this work we have investigated structural, optical and magnetic behavior of Co doped ZnO thin films by varying the doping concentration from 0-10%. The films have been deposited on corning glass (7059) and Si (100) substrates using sol-gel spin coating method and annealed at 550° C in air. The films were found to possess c-axis orientation and exhibited polycrystalline hexagonal wurtzite structure. The grain size was estimated by the Debye-Scherrer’s and Williamson-Hall plots. The Raman spectra of thin films recorded at room temperature in backscattering mode showed the prominent peaks at 302 cm-1, 434 cm-1,490 cm-1, 520 cm-1 and 715 cm-1. For Co doped ZnO thin films, the intensity of the peaks at 490 cm-1 and 715 cm-1 corresponding to the spinel structure of ZnCo2O4 sharpen with the increase in Co concentration. Undoped ZnO thin film were transparent (>90%) in the visible region which further reduces with the Co doping. Optical bandgap of Co doped ZnO thin films has been estimated using tauc’s plot. M-H and M-T curves derived from vibrating sample magnetometer and physical property measurement system show ferromagnetism in Co doped ZnO thin films.