微量K掺杂对样品La_(0.75)Sr_(0.25-x)K_xMnO_3的磁性、电输运及室温磁电阻的影响

Influence of K Doping on the Magnetic,Electrical Transport and Magnetoresistance of La_(0.75)Sr_(0.25-x)K_xMnO_3 at Room Temperature

采用溶胶-凝胶方法制备了系列样品La_（0.75）Sr_（0.25-x）K_xMnO_3（x=0.00,0.05,0.07,0.10）。对系列样品进行了相结构、磁性和电输运性质的研究。XRD数据表明：系列样品具有完整的钙钛矿锰氧化物结构。通过对磁性和电阻率的研究发现：与双交换作用相比,A位离子的无序度2对样品的磁性和电输运的影响起主要作用。随掺杂量的增加,磁电阻的峰值逐渐增大;峰值温度逐渐下降,更接近室温。在210-280 K的温区内,磁电阻基本保持稳定。这些结果都有利于磁电阻的实际应用。

A series of samples La_（0.75）Sr_（0.25-x）K_xMnO_3（ x = 0,0. 05,0. 07,0. 10） were prepared by sol-gel method. Phase structure,magnetic properties and electrical transport effect of the series of samples were studied. Through the study of the phase structure,it has been found that the samples have complete perovskite manganese oxide structure. Through the study of magnetic and electrical resistivity, the influence of the disorder degree 2 of A-site ions on the magnetic and electrical transport of the samples is larger. With the increase of x,the peak value of MR increases gradually,but the peak temperature is gradually decreased,and so it is more close to the room temperature. In the temperature range of 210-280 K,the MR keeps the same,which is beneficial to the practical application.