The structure and magnetotransport properties of La_2/3Sr_1/3MnO₃/Ba(La)TiO₃ composites

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• 作者：Z.Y. Zhou ; G.S. Luo ; F.Y. Jiang
• 关键词：Manganites ; Magnetoresistance ; Spin-dependent scattering and tunneling
• 刊名：Journal of Magnetism and Magnetic Materials
• 出版年：2009
• 出版时间：July 2009
• 年：2009
• 卷：321
• 期：13
• 页码：1919-1923
• 全文大小：475 K

文摘

The effect of Ba(La)TiO₃ doping on the structure and magnetotransport properties of La_2/3Sr_1/3MnO₃(LSMO)/xBa(La)TiO₃ (x=0.0, 1.0, 5.0 mol % ) have been investigated. The X-ray diffraction patterns and microstructural analysis show that BaTiO₃ and LSMO phases exist independently in BaTiO₃-doped composites. The metal–insulator transition temperature (T_MI) decreases whereas the maximum resistivity increases very quickly by the increase of BaTiO₃ doping level. The partial substitution of Ba by La(0.35 mol % ) results in a decrease in resistivity of LSMO/xBa(La)TiO₃ composites. Magnetoresistance of BaTiO₃-doped composites decreases monotonously in the temperature range 200–400 K in a magnetic field of 5 T, which is completely different from that of LSMO compound. The value of MR decreases at low field (H<1 T) and increases at high fields (H>1 T) with increasing the BaTiO₃ doping level at low temperatures below 280 K. These investigations reveal that the magnetotransport properties of LSMO/xBa(La)TiO₃ composites are dominated by spin-dependent scattering and tunneling effect at the LSMO/BaTiO₃/LSMO magnetic tunnel junction.