Exploration of Ti0.9Fe0.1-xNixO2 thin films as dilute magnetic semiconductors

Abstract

In this research work a series of Ti0.9Fe0.1-xNixO2 thin films with Ni concentration varying from x=0 to 0.1 have been grown onto single crystal Si (100) substrate by pulsed laser deposition. The two ferromagnetic impurities Fe and Ni were co-doped in TiO2 films simultaneously in order to enhance their optical, magnetic and electrical properties. The targets for the deposition of thin films have been prepared via solid state reaction route. The thin film samples were annealed in air at 800°C for two hours in order to control their phase stability, carrier concentration and magnetic properties. Their structural properties were studied by X-ray diffractometer, which revealed rutile phase of TiO2. The film surface morphology, observed by scanning electron microscopy, was porous and smooth with the structure of rutile phase. The magnetic properties were investigated by vibrating sample magnetometry at room temperature and showed a ferromagnetic behavior for all the thin films. The optical properties, investigated by spectroscopic ellipsometry revealed a red shift in band gap energy as a function of Ni contents. Electrical characterization has been done by four probe Hall effect measurements at room temperature. The N-type semiconducting behavior has been observed at x=0, 0.02, 0.04 and 0.06 and p-type behavior for x=0.08 and 0.1. P-type conductivity is required for use in spintronics devices.