Crossover from negative to positive magnetoresistance in superconductor/ferromagnet composites thick films

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• 作者：O. Paredes ; E. Baca ; D. Fuchs ; O. Morá ; n
• 关键词：Thick films ; Superconductivity ; Ferromagnetism ; Composites
• 刊名：Physica C
• 出版年：2010
• 出版时间：15 November 2010
• 年：2010
• 卷：470
• 期：21
• 页码：1911-1915
• 全文大小：469 K

文摘

Thick films of ((Bi, Pb)₂Sr₂Ca₂Cu₃O_x)_0.95/(LaSr_0.7Mn_0.3O₃)_0.05 [(Bi-2223)_0.95(LSMO)_0.05] composites were fabricated on (0 0 1)-oriented LaAlO₃ substrates by a simple melting–quenching–annealing method and their structural, morphological and magnetoelectrical properties carefully studied. Analysis of the X-ray diffraction patterns suggested a highly oriented growth along the c-axis of LSMO. This preferred orientation, with the crystal c-axis being perpendicular to the plane of the substrate, was considered to be indicative of a textured growth mode. Electrical and magnetic measurements showed the presence of ferromagnetism and superconductivity in the composite at temperatures above room temperature and below T50 K, respectively. A clear crossover from negative to positive magnetoresistance was observed at 80 K in a magnetic field as strong as 5 T.