Temperature stability of magnetoresistance (MR) and MR enhancement in La_(1-x)(Sr_(1-y)Ag_y)_x MnO_3 system  

作　　者：Yong-Gang Tang Gui-Ying Wang Guo-Qing Yan Qi-Xiang Song Ming-Yu Zhang Zhen-Sheng Peng 

机构地区：[1]Cultivating Base of Anhui Key Laboratory of Spintronics and Nano-Materials Research [2]School of Mechanical and Electronic Engineering, Suzhou University

出　　处：《Rare Metals》2013年第1期81-86,共6页稀有金属（英文版）

基　　金：financially supported by the National Natural Science Foundation of China(NSFC)(No.19934003);the Key Program of Natural Science Foundation of Anhui Province(No.KJ2011A259);the Program of Professors and Doctors'Research Startup Foundation of Suzhou College(Nos.2011jb01 and 2011jb02);the Cultivating Base of Anhui Key Laboratory of Spintronics and Nano-materials Research Program(No.2010YKF04)

摘　　要：Polycrystalline samples of Lal-x（Srl-yAgy）x MnO3 （y = 0.0, 0.2, 0.4, 0.6, 1.0） were prepared by the solid-state reaction method. The temperature stability of magnetoresistance and magnetoresistance enhancement in Lal_x（Srl_yAgy）~MnO3 system with both univalent and bivalent elements doped at A site and with unchanged value of Mn~＋/Mn4＋ ratio were explored through the measurements of X-ray diffraction patterns, magnetiza- tion-temperature （M-T） curves, resistivity-temperature （p-T） curves and magnetoresistance-temperature （MR-T） curves. The results are as follows： there are two peaks in the p-T curves of the samples with Ag doping, one is caused by resistance change during the paramagnetism- ferromagnetism transition, and the other is from boundary- dependent scattering of conduction electrons on the boundaries of grains. The peak value of MR increases with increasing Ag doping content, and it increases from 8.2 % for y ---- 0.2 to 29.6 % for y ---- 1.0 under the magnetic field of B = 0.8 T; MR remains a constant of 12 % in the temperature range of 218-168 K for the sample with y = 1.0, and the temperature stability of MR is in favor of the practical application of MR.Polycrystalline samples of Lal-x（Srl-yAgy）x MnO3 （y = 0.0, 0.2, 0.4, 0.6, 1.0） were prepared by the solid-state reaction method. The temperature stability of magnetoresistance and magnetoresistance enhancement in Lal_x（Srl_yAgy）~MnO3 system with both univalent and bivalent elements doped at A site and with unchanged value of Mn~＋/Mn4＋ ratio were explored through the measurements of X-ray diffraction patterns, magnetiza- tion-temperature （M-T） curves, resistivity-temperature （p-T） curves and magnetoresistance-temperature （MR-T） curves. The results are as follows： there are two peaks in the p-T curves of the samples with Ag doping, one is caused by resistance change during the paramagnetism- ferromagnetism transition, and the other is from boundary- dependent scattering of conduction electrons on the boundaries of grains. The peak value of MR increases with increasing Ag doping content, and it increases from 8.2 % for y ---- 0.2 to 29.6 % for y ---- 1.0 under the magnetic field of B = 0.8 T; MR remains a constant of 12 % in the temperature range of 218-168 K for the sample with y = 1.0, and the temperature stability of MR is in favor of the practical application of MR.

关 键 词：Ag doping Magnetoresistance enhancement Temperature stability Perovskite manganite 

分 类 号：O611.3[理学—无机化学]