Half metallic Fe3O4 : An experimental study on impurity doping and the giant magnetoresistance effect

This thesis provides a detailed insight into the effects of impurity doping on half metallic Fe3O4 films to explore new magnetic materials, and subsequently investigates the giant magnetoresistance (GMR) phenomenon in Fe3O4 incorporated multilayers and granular systems for potential applications in oxide spintronics. A systematic analysis of the evolution in microstructural, magnetic and magnetotransport properties of Co and Cu doped Fe3O4 films is presented and marked changes are observed as the impurity concentration is varied, due to substitution of Fe ions in the inverse spinel structure of Fe3O4. The GMR effect, examined in detail for a Fe3O4/Cu/Ni80Fe20 pseudo spin valve trilayer in the current perpendicular to plane (CPP) and the current-in-plane (CIP) configurations, shows strong dependence on spacer layer thickness and is compared with existing theoretical models. Interestingly, the GMR effect is also observed for a completely oxide based, non-multilayer Fe3O4-Al2O3 granular system, and is isotropic in nature.

Author dc:creator

• TRIPATHY DEBASHISH

• Half Metals, Fe3O4, Impurity Doping, Giant Magnetoresistance, Granular Films, Spin dependent tunneling