• Title/Summary/Keyword: magnetorsistive effects

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Crystal Structure and Electrical Transport Characteristics of ${La_{1-x}}{Sr_x}{MnO_{3-{\delta}}}$(0.19$\leq$x$\leq$0.31) Thin Films (${La_{1-x}}{Sr_x}{MnO_{3-{\delta}}}$(0.19$\leq$x$\leq$0.31) 박막의 결정구조 및 전기전도 특성)

  • Heo, H.;Lim, S.J.;Cho, N-H.
    • Korean Journal of Materials Research
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    • v.10 no.6
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    • pp.437-444
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    • 2000
  • We investigated the effect of substrate temperature, chemical composition and post-deposition heat-treatment on the crystal structure and electrical transport of $La_{1-x}Sr_xMnO_{3-{\delta}}$(0.19${\leq}x{\leq}$0.31) thin films. As-prepared $La_{1-x}Sr_xMnO_{3-{\delta}}$ films grown at $500^{\circ}C$ by sputter techniques were found to have the pseudo-tetragonal system(a/c=0.97) and a highly preferential <001> orientation. The films were changed to be of the cubic system by post-deposition annealing at around $900^{\circ}C$. A main target of $La_{0.67}Sr_{0.33}MnO_3$ as well as auxliary targets of $La_{0.3}Sr_{0.7}MnO_3$ ceramics were co-sputtered to control the chemical composition of the film. The Sr content(x) of the film ranged from 0.19 to 0.31, depending on the number of the auxiliary target. When x increased from 0.19 to 0.31, the electrical resistivity of the film decreased and the transition temperature between metal and semiconductor shifted to higher temperature. With a magnetic field of 0.18 T, the magneto-resistance ratio (MR(%) = (${\rho}_o-{\rho}_H/{\rho}_H$) of the $La_{0.69}Sr_{0.31}MnO_3$ thin film was about 390%.

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