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### Al掺杂对La0.8Sr0.2Mn1-xAlxO3电输运性能的影响

1. 1. 河海大学 理学院,南京210093;
2. 中国科学技术大学 物理学院, 合肥 230026
• 收稿日期:2022-07-14 修回日期:2022-09-05
• 作者简介:张爱梅(1978-), 女, 教授. E-mail: amzhang2009@hhu.edu.cn.
• 基金资助:
国家自然科学基金(11404091); 江苏省自然科学基金(BK20140839);

### Effects of Al Doping on the Structure and Electrical Transport Property of La0.8Sr0.2Mn1-xAlxO3

ZHANG Aimei1, ZHU Jiajia1, FANG Tiancheng2, PAN Xixi1

1. 1. College of Science, Hohai University, Nanjing 210093, China;
2. College of Physics, University of Science and Technology of China, Hefei 230026, China
• Received:2022-07-14 Revised:2022-09-05
• About author:ZHANG Aimei (1978-), female, professor. E-mail: amzhang2009@hhu.edu.cn
• Supported by:
National Natural Science Foundation of China (11404091); Natural Science Foundation of Jiangsu Province (BK20140839)

Abstract: As a colossal magnetoresistance material, the perovskite manganese oxide La1-xSrxMnO3 has broad application prospects in magnetic sensors and other fields. However, it is difficult to obtain a significant colossal magnetoresistance effect at a low magnetic field and room temperature. In order to improve its magnetoresistance effect and transition temperature, La0.8Sr0.2Mn1-xAlxO3 (0≤x≤0.25) (LSMAO) polycrystalline samples were prepared by the traditional solid-state reaction method in this study. The effects of Al doping on the electrical transport property and magnetoresistance effects of LSMO were systematically analyzed. The X-ray diffraction (XRD) results indicate that all the samples crystallize in a single rhombohedral structure with the space group of R3̅C. The study of electrical transport property shows that the resistivity of the samples increases exponentially with the doping of Al3+, and the metal-insulator transition temperature is increased by an external magnetic field. This may be due to the dilution of the Mn3+/Mn4+ ions network by Al3+, which increases the magnetic disorder while reducing the number of carriers. In addition, the conduction mechanism of LSMAO ceramics changes from the small polaron hopping model (SPH) to the variable range hopping model (VRH) with the doping of Al3+, reflecting that the non-magnetic Al3+ suppress the carrier exchange between the ferromagnetic clusters. As a result, the thermally activated neighbor transition process of small polarons is suppressed. The magnetoresistance value of LSMAO is enhanced from 21.03% to 59.71% with x increasing from 0 to 0.25, which proves that the doping of Al3+ can effectively enhance the magnetoresistance effect of LSMAO.