【摘要】 研究了用固相反应法制备亚锰酸盐多晶样品La0.7-xYxCa0.3MnO3,并研究了Y的不同掺杂(x=0.1,0.2)对样品的晶体结构、电磁特性和磁电阻效应的影响.实验结果表明,随着温度的降低,x=0.1样品的R-T曲线没有出现峰值,而x=0.2样品出现了峰值,显示了复杂的输运特性.两种样品的磁电阻Rm都随着温度的降低而升高,但都没有出现峰值.x=0.2的样品在较宽的温区内,磁电阻效应都很显著,而且Y掺杂由x=0.1提高至x=0.2,磁电阻效应增强.更多还原

【Abstract】 This paper discusses the preparation of the manganite polycrystalline samples La0.7-xYxCa0.3MnO3 by the solid-state reaction technique. The effects that the different substitution of Y for La affects the crystal structure, electromagnetic properties and magnetoresistance effects are also studied. No peak is observed on the resistance-temperature curves(R-T curves) of the sample La0.6Y0.1Ca0.3MnO3 with the decrease of the tempeature, whereas onepeak is observed for the sample La0.5Y0.2Ca0.3MnO3, and the complex transport properties are shown. The magnetoresistance(Rm) of the two samples increases with the decrease of the temperature, but no peak is observed. The sample La0.5Y0.2Ca0.3MnO3 shows large magnetoresistance over a wide temperature range, moreover, the magnetoresistance effects strengthen with the increase of Y substituting for La from x=0.1 to x=0.2.更多还原