Anisotropic Magnetoelastic Phenomena in Layered Manganite Crystals: Implication of Change in Orbital State
Anisotropic Magnetoelastic Phenomena in Layered Manganite Crystals: Implication of Change in Orbital State
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层状锰酸盐晶体中的各向异性磁弹性现象：轨道状态变化的含义
DOI：
10.1103/physrevlett.81.5920
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发表时间：
1998
影响因子：
8.6
通讯作者：
Y. Tokura
中科院分区：
文献类型：
--
作者：
T. Kimura;Y. Tomioka;A. Asamitsu;Y. Tokura
研究了双层锰酸盐晶体与磁阻现象相关的磁弹性现象， ${\mathrm{La}}_{2\ensuremath{-}2x}{\mathrm{Sr}}_{1+2x}{\mathrm{Mn}}_{2}{\mathrm{O}}_{7}$ ( $0.3\ensuremath{\le}x\ensuremath{\le}0.45$)，通过在磁场中平行和垂直于 ${\mathrm{MnO}}_{2}$ 平面的严格测量。磁化过程不仅产生大的负磁阻，而且产生相对于晶轴具有高度各向异性的巨大晶格限制。晶格严格的大小和符号随着掺杂水平（$x$）而系统地变化，这应该反映二维导带中轨道相关的占据随温度、磁场和掺杂水平的变化。
Magnetoelastic phenomena correlated with magnetoresistive ones have been investigated for bilayered manganite crystals, ${\mathrm{La}}_{2\ensuremath{-}2x}{\mathrm{Sr}}_{1+2x}{\mathrm{Mn}}_{2}{\mathrm{O}}_{7}$ ( $0.3\ensuremath{\le}x\ensuremath{\le}0.45$), by measurements of the striction parallel and perpendicular to the ${\mathrm{MnO}}_{2}$ plane in magnetic fields. The magnetization process causes not only a large negative magnetoresistance but also a gigantic lattice striction which is highly anisotropic with respect to the crystal axes. The magnitude and the sign of the lattice striction systematically varies with the doping level ( $x$), which should reflect variation of the orbital-dependent occupancy in the two-dimensional conduction band with temperature, magnetic field, and doping level.