Structural and magneto-transport properties of (La_0.6Ca_0.2Sr_0.2MnO₃)_{1鈭?span style='font-style: italic'>x} (Sb₂O₃/CuO)_x composites

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• 作者：M. Nasri ; M. Triki ; E. Dhahri ; P. Lachkar ; E.K. Hlil
• 关键词：B. Composite ; B. Grain boundaries ; Magnetoresistance ; Spin dependent transport
• 刊名：Ceramics International
• 出版年：January, 2014
• 年：2014
• 卷：40
• 期：1_part_PB
• 页码：2023-2028
• 全文大小：2476 K

文摘

The (La_0.6Ca_0.2Sr_0.2MnO₃)_1鈭?em>xem>(Sb₂O₃/CuO)_<em>xem> (<em>xem>=0.00, 0.03, 0.07, 0.12 and 0.18) composites were prepared by the solid-state reaction technique. (La_0.6Ca_0.2Sr_0.2MnO₃)_1鈭?em>xem>(Sb₂O₃/CuO)_<em>xem> are identified by X-ray diffraction and SEM analysis as a two phases consisting of ferromagnetic manganite phase and Sb₂O₃/CuO phase. Magnetic measurement reveals that the Curie temperature as well as the saturation value of magnetization is gradually weakened by Sb₂O₃/CuO addition. The temperature dependence of resistivity shows that the transport behavior of the composites is governed by the grain boundaries. It is suggested that the Sb₂O₃ addition, acts as a separation layer between grains. Whereas, the introduction of CuO into the grain boundaries forms artificial conducting network and improves the carrier to transport. The maximum magnetoresistance was observed to be 鈮?0% at 10 K for <em>xem>=0.03 which is larger than the largest MR value of pure La_0.6Ca_0.2Sr_0.2MnO₃ (40% at 10 K) in a 2 T magnetic field. Enhanced MR effect at a wide temperature range is consistent with the disorder-driven amplification of spin-dependent transport.