Preparation and magnetocaloric effect of (La_(0.67-X)Gd_X)Sr_(0.33)MnO_3 (X = 0.1, 0.15) nanoparticles

摘要

We report a new route to synthesize nano-sized (La_(0.67-X)Gd_X)Sr_(0.33)MnO_3 (X = 0.1, 0.15) perovskite crystalline complex oxides at calcination temperatures of 600-900℃ using amorphous molecular alloy as precursor. The precursor could completely decompose into oxide at temperatures below 500 ℃ according to thermogravimetric analysis and differential thermal analysis results. X-ray diffraction demonstrated that the decomposed species was composed of perovskite structure at a calcination temperature of 600 ℃ for 2 h. The size and topography of the oxides are dependent on the calcination temperature of the precursor. The resulting particle size is in the range of 40-120 nm as determined by a transmission electron microscope. This method is effective and can be easily quantitatively controlled to synthesize nanosized perovskite complex oxides. The Curie temperature TC and the magnetocaloric effect of (La_(0.67-X)Gd_X)Sr_(0.33)MnO_3 (X = 0.1, 0.15) nanoparticles are discussed based on the measurement of the low-field magnetization curve and the isothermal magnetization curve.