Strain-induced insulator state and giant gauge factor of La0.7Sr0.3CoO3 films
Strain-induced insulator state and giant gauge factor of La0.7Sr0.3CoO3 films
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DOI：
10.1103/physrevlett.100.076401
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发表时间：
2008-02-22
影响因子：
8.6
通讯作者：
Doerr, K.
中科院分区：
文献类型：
--
作者：
Rata, A. D.;Herklotz, A.;Doerr, K.
对于铁磁 La0.7Sr0.3CoO3 薄膜，观察到应变引起的电导率变化了几个数量级。人们发现拉伸应变可以驱动窄带金属高度绝缘。使用压电基板施加的可逆应变揭示了巨大的电阻调制，包括 300 K 下 7000 的巨大压阻应变系数。记录的静态和可逆应变薄膜的磁化数据显示出适度的变化。这表明低温Co自旋态的应变响应相当弱。我们认为，CoO6 单元的应变引起的静态 Jahn-Teller 型变形可能提供一种局域化机制，该机制也对顺磁体系中的电子传输产生影响。
A strain-induced change of the electrical conductivity by several orders of magnitude has been observed for ferromagnetic La0.7Sr0.3CoO3 films. Tensile strain is found to drive the narrow-band metal highly insulating. Reversible strain applied using a piezoelectric substrate reveals huge resistance modulations including a giant piezoresistive gauge factor of 7000 at 300 K. Magnetization data recorded for statically and reversibly strained films show moderate changes. This indicates a rather weak strain response of the low-temperature Co spin state. We suggest that a strain-induced static Jahn-Teller-type deformation of the CoO6 units may provide a localization mechanism that also has impact on electronic transport in the paramagnetic regime.