Enhancement of room-temperature magnetoresistance in La0.6Dy0.1Sr0.3MnO3/Agx

• Published in: Rare metals Vol. 29; no. 2; pp. 126 - 131
• Main Authors: Song, Qixiang, Niu, Xiaofei, Wang, Guiying, Tang, Yonggang, Cai, Zhirang, Peng, Zhensheng
• Format: Journal Article
• Language: English
• Published: Beijing University of Science and Technology Beijing 2010
• Subjects: Biomaterials; Chemistry and Materials Science; Energy; Materials Engineering; Materials Science; Metallic Materials; Nanoscale Science and Technology; Physical Chemistry; 固相反应法; 复合材料; 掺杂量; 氧化物体系; 氧化银; 磁电阻效应; 自旋极化; room temperature; low-field magnetoresistance; perovskite manganite; two-phase composite
• ISSN: 1001-0521; 1867-7185
• DOI: 10.1007/s12598-010-0022-6

The samples of La0.6Dy0.1Sr0.3MnO3/（Ag2O）x/2（x = 0.00, 0.02, 0.04, 0.06, 0.08, 0.10, 0.20, 0.25, and 0.30） were prepared by using the solid-state reaction method.Their magnetic property, transport behavior, transport mechanism and magnetoresistance effect were studied through the measurements of magnetization-temperature（M-T） curves, ρ-T curves and the fitting of ρ-T curves.The results indicated that Ag could take part in the reaction when the doping amount is small.However, when the doping amount is comparatively large, Ag as metallic state mainly deposits on the grain boundary of La0.6Dy0.1Sr0.3MnO3, and then the system forms a two-phase composite.When the Ag doping amount is 30% mole ratio, the resistivity of the sample is one order of magnitude smaller than that of low doped samples, and its peak of magnetoresistance at 292 K and in the magnetic field of 0.2 T strengthens apparently and reaches 16.3%, which is over 7 times as large as 2.2% of La0.6Dy0.1Sr0.3MnO3.The two-phase composite system of magnetoresistance based on perovskite manganite consists of two parts：intrinsic magnetoresistance and extrinsic magnetoresistance.However, extrinsic magnetoresistance comes from spin-dependent scattering（SDS） and spin-polarized tunneling（SPT）.Magnetoresistance near TC increases due to the contribution of intrinsic magnetoresistance and extrinsic magnetoresistance formed by SDS, and magnetoresistance at low temperature is extrinsic magnetoresistance formed by SPT.