Facile sol-gel method derived Au nanoparticles decoration nickel ferrites thin films: Effect on optical and magnetic properties

Abstract

Noble metal Au nanoparticles (Au NPs) decoration nickel ferrite (hereafter abbreviated as NFA-x, x = 0, 0.04, 0.08 and 0.12) thin films were synthesized on quartz and Pt/Ti/SiO2/Si substrates by a facile sol-gel method. The structural, optical and magnetic performances of NFA-x thin films have been investigated. The XRD patterns revealed the formation of cubic spinel ferrite structure. The SEM analysis indicated that NFA-x thin films were dense and uniform, which also confirm that crystalline size decreased with increasing of Au content. A remarkable surface plasmon resonance (SPR) features has been observed in NFA-0.12 films. The optical band gap of NFA-x thin films decreased with increasing Au concentration. In addition, our results revealed that the magnetism was highly depending on the Au concentration. The saturation magnetization remarkable decreased then sharply increased with increasing of Au content, which is attributed to Au NPs decoration effect. However, the coercive field and squareness ration showed increasing trend with increasing of Au concentration. Our work suggests that Au nanoparticles decoration nickel ferrites thin films have promising applications in multifunctional materials field.