Preparation and Characteristics of Manganite Materials

• Main Authors: Chen, Jin-Wen, 陳敬文
• Other Authors: 洪夢聰
• Format: Others
• Language: zh-TW
• Published: 2008
• Online Access: http://ndltd.ncl.edu.tw/handle/08983157314317113436

碩士 === 正修科技大學 === 電機工程研究所 === 96 === The transport properties, temperature coefficient of resistance, magnetoresistance, microstructure and surface morphology of La0.7CaxSr0.3-xMnO3 and La1-xBxMnO3 have been systematically investigated in this study. Experimental results show that the metal-insulator transition temperature (Tp) increases with increasing Sr. However, the resistance decreases with increasing Sr. The maximum value of temperature coefficient of resistance (TCRmax) is promoted with increasing Ca. The magnetoresistance of La0.7CaxSr0.3-xMnO3 increases with decrease temperature except for La0.7Ca0.3MnO3. The maximum value of magnetoresistance (MRmax) is -39.7% under applied magnetic field of 1Tesla. The grain size of La0.7CaxSr0.3-xMnO3 increases with increasing Ca from the analysis of X-ray diffraction (XRD) results. However the grain size of La1-xBxMnO3 increases with decreasing Ba. The similar results have also been observed by scanning electron microscopy (SEM).