INFLUENCE OF NANO-SIZED TiO2 ON Pr0.7Sr0.3MnO3 COMPOSITES: STRUCTURAL, MICROSTRUCTURAL AND MAGNETIC PROPERTIES

Abstract

Perovskite manganites have always been the research interest attributed to its intriguing colossal magnetoresistive (CMR) properties. Incorporation of an insulating secondary phase into the manganite composites has proven as an effective measure to enhance the low field magnetoresistance (LFMR). This paper reports the structural, microstructural and magnetic properties of Pr_0.7Sr_0.3MnO₃ (PSMO) composites synthesized by the solid state reaction method. Different compositions of nano-sized TiO₂ (5 %, 10 %, 15 % and 20 %) were appended into the samples to study the effect on the physical properties. X ray diffraction patterns show all samples exhibit polycrystalline PSMO as the major phase and strong orientation along (121) direction throughout the series. The microstructural parameter is presented by Rietveld refinement and indicates that TiO₂ only presents in 20 % samples. Nano-size TiO₂ has distorted the pure PSMO phase as there are other minor phases observed in the manganite composites. Crystallite size of PSMO composites is ranging from 37.7 – 63.2 nm with no direct relation to the TiO₂ content. Surface roughness and particle size show the increment along with increasing TiO₂ composition from the atomic force microscope (AFM) analysis. All samples possess the narrow hysteresis loop with weak ferromagnetic nature at room temperature. The PSMO: TiO₂ presented in this study is a promising manganite composite which could be utilized in the future spintronic applications with its interesting physical properties.