SYNTHESIS & CHARACTERIZATION OF NANOCRYSTALLINE MULTIFERROIC Bil _xLa,,Fe03 AND Bio.9_ySmyLao.iFeO3 THIN FILMS

Abstract

Multiferroic Bii. LaFe03 (BLFO) and Bi0,9_ySmyLao,1FeO3 (BSLFO) thin films are formed by pulsed laser deposition technique. The effect of La doping in BFO and the effect of Sm doping in BLFO films is studied by using various experimental techniques. The effect of doping on structural, surface morphological, optical and magnetic properties are studied by using a X-ray diffractometer, Atomic force Microscope, UV-VIS-NIR spectrophotometer and SQUID magnetometer respectively. The structure is found to be stabilized on addition of La in BFO and Sm in BLFO respectively and also the effect on grain size is described. The AFM studies confirm the observed variation in grain size. The transmission spectra obtained from a UV-VIS-NIR spectrophotometer in the wavelength region 200-2000 nm is used to calculate various optical parameters. The effect of doping on transmittance, refractive index and direct & indirect band gap is studied. The magnetic hysteresis loops at 5K and 300K are obtained for both type of films and the effect of doping on magnetic parameters like remanent magnetization, saturation magnetization and coercivity is described. Also, the variation of magnetization and magnetic susceptibility with temperature is studied in the temperature range from 5K to 300K.