Temperature stability of magnetoresistance （MR） and MR enhancement in La1-x(Sr1-yAgy)x MnO3 system
来源期刊：Rare Metals2013年第1期
论文作者：Yong-Gang Tang Gui-Ying Wang Guo-Qing Yan Qi-Xiang Song Ming-Yu Zhang Zhen-Sheng Peng
文章页码：81 - 86
摘 要：Polycrystalline samples of La12x（Sr12yAgy）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 La1-x（Sr1-yAgy）x MnO 3 system with both univalent and bivalent elements doped at A site and with unchanged value of Mn3+ /Mn4+ ratio were explored through the measurements of X-ray diffraction patterns, magnetiza-tion-temperature （M-T） curves, resistivity-temperature （q-T） curves and magnetoresistance-temperature （MR-T） curves. The results are as follows: there are two peaks in the q-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.
Yong-Gang Tang1,2，Gui-Ying Wang1,2，Guo-Qing Yan1,2，Qi-Xiang Song1,2，Ming-Yu Zhang1,2，Zhen-Sheng Peng1
1. Cultivating Base of Anhui Key Laboratory of Spintronics and Nano-Materials Research2. School of Mechanical and Electronic Engineering, Suzhou University
摘 要：Polycrystalline samples of La12x（Sr12yAgy）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 La1-x（Sr1-yAgy）x MnO 3 system with both univalent and bivalent elements doped at A site and with unchanged value of Mn3+ /Mn4+ ratio were explored through the measurements of X-ray diffraction patterns, magnetiza-tion-temperature （M-T） curves, resistivity-temperature （q-T） curves and magnetoresistance-temperature （MR-T） curves. The results are as follows: there are two peaks in the q-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.
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