Annealing temperature effect on magnetic and magnetocaloric properties of manganites

作者：Mohamed Abd El Moez A^*; Vega V; Ipatov M; Ahmed A M; Hernando B

来源：Journal of Alloys and Compounds, 2016, 665: 394-403.

DOI：10.1016/j.jallcom.2016.01.057

• Composite materials
• Rare earth alloys and compounds
• Grain boundaries
• Magnetization
• Magnetocaloric effect

In this work, we investigate the effect of annealing process at different temperatures (600 and 800 degrees C) on structural, magnetic and magnetocaloric properties of La0.7Ba0.3MnO3/xTiO(2) system with x = 0.04 and 0.06. Crystal structure analysis shows the R-3c rhombohedral symmetry for composites in both annealing temperatures indicating structure stability. Magnetization and coercive field of doped composites increase with increasing annealing temperature, while there is no effect on their Curie temperature (T-c) that remains constant at 348 K due to the TiO2-La0.7Ba0.3MnO3 interaction lack. Increasing annealing temperature is found to be an effective process that can positively affect the magnetocaloric properties. Where, the relative cooling power of doped composites increases from 50 to 62 J/kg for x = 0.04 composite and from 54 to 66 J/kg for x = 0.06 composite with increasing annealing temperature from 600 to 800 degrees C. Moreover, the experimental results of magnetic entropy change have been modulated using Landau theory and the calculations have indicated the negligible contribution of elastic, magnetoelastic and magnetoelectronic coupling in the magnetocaloric properties of La0.7Ba0.3MnO3/xTiO(2) system in both annealing temperatures.

• 出版日期2016-4-25