Jun Ding
National University of Singapore, Singapore
Title: Spinel ferrite films with enhanced magnetization and large magneto-resistance
Biography
Biography: Jun Ding
Abstract
Spinel ferrite (MFe2O4 with M = Fe, Co, Ni and Mn) is an important family on magnetic materials for various engineering applications. However, their saturation magnetization is much lower compared to metallic compounds. Recently, enhanced magnetization has been reported in ultrathin spinel ferrite films. Our study on spinel ferrite on various substrates has indicated that the magnetization enhancement may be attributed to a large area of grain boundaries because of very small grain size in order of 4-5 nm. More recently, we have successfully fabricated spinel ferrite films on MgO substrate using chemical route – thermal decomposition. Epitaxial thick films can be deposited on MgO substrates of different crystallographic orientations. More interesting, these thick films exhibit enhanced magnetization over 1 Tesla. Our structural investigation has indicated that the enhanced magnetization may be attributed to doping of carbon because carbon substitution may lead in spin flip. The results have been supported by first principles calculation.