Anomalous positive magnetoresistance in Cox–C1−x granular films on Si substrates
Anomalous positive magnetoresistance in Cox–C1−x granular films on Si substrates
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DOI：
10.1063/1.1641523
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发表时间：
2004-01
影响因子：
3.2
通讯作者：
D. Zhu;Xiaozhi Zhang;Q. Xue
中科院分区：
文献类型：
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作者：
D. Zhu;Xiaozhi Zhang;Q. Xue
报道了用脉冲激光沉积法在Si（100）衬底上制备的Cox-C1−x颗粒膜中的反常正磁电阻（PMR）。在磁场B=1 T和x=2时，正MR大得多，高达22%。%，在室温下比在低温下观察到。有趣的是，当B 1 T时，室温响应具有B 2/3依赖性。与低温PMR不同，室温PMR与Si（100）衬底有关。此外，我们还发现，低温下的本征正MR是由局域电子态的波函数收缩引起的，而Cox-C1−x/Si结构的非本征MR效应显然是由另一种机制决定的，这种机制可能存在于其他类似结构中。这反过来又对这些材料的优化具有重要意义。
We report the anomalous positive magnetoresistance (PMR) in Cox–C1−x granular films prepared on Si(100) substrates by pulsed laser deposition method. A much larger positive MR, up to 22% at magnetic field B=1 T and x=2 at. %, is observed at room temperature than at low temperature. Interestingly, the room-temperature response has a B2/3 dependence when B 1 T. Different from the low-temperature PMR, the room-temperature PMR are related with the Si(100) substrates. Furthermore, we show that the intrinsic positive MR at low temperature arise from shrinkage of the wave functions of localized electronic states, while the extrinsic MR effects of the Cox–C1−x/Si structure are obviously determined by another mechanism, which may exist in other similar structures. This in turn has important implications for the optimization of such materials.