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Quantum Transport Phenomena of Two-Dimensional Electron Sysytems in GaAs/AlGa4s heterostructures with a small Ferromagnetic Thin Film

小铁磁薄膜 GaAs/AlGa4s 异质结构中二维电子系统的量子输运现象

基本信息

批准号：
15540320
负责人：
WAKABAYASHI Junichi
金额：
$ 1.41万
依托单位：
CHUO UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2003
资助国家：
日本
起止时间：
2003 至 2004
项目状态：
已结题

项目摘要

The purpose of the present research is to investigate the origin of the anomalous magnetoresistance observed in GaAs/A1GaAs heterostructure with a single ferromagnetic thin film in a strong magnetic field. We have investigated (1) the electron density dependence of the anomalous magnetoresistance, and (2) the effects of the local magnetic field profile produce by the ferromagnetic thin film on the anomalous magnetoresistance.In order to perform the experiment (1), we have fabricated GaAs/A1GaAs heterostructure samples with a gate electrode and varied electron density and the electron mobility simultaneously. The results analyzed on the phase diagram, electron density vs. electron mobility, show that there is no correlation between the anomalous magnetoresistance and the electron density.For the experiment (2), we have fabricated GaAs/A1GaAs heterostructure samples with different distance between a ferromagnetic thin film and the two dimensional electron systems, and with different size, thickness, and shape of a ferromagnetic thin film. The results strongly suggest that there is a correlation between the anomalous magnetoresistance and the minimum of the magnetic filed profile produce by the ferromagnetic thin film. However, we cannot explain consistently all the results of the present experiments.

本研究的目的是探讨GaAs/A1 GaAs异质结中所观察到的异常磁电阻的起源与一个单一的铁磁薄膜在强磁场。我们研究了（1）反常磁电阻与电子密度的关系，（2）铁磁薄膜产生的局域磁场分布对反常磁电阻的影响，为了完成实验（1），我们制备了具有栅电极的GaAs/Al_1GaAs异质结构样品，同时改变了电子密度和电子迁移率。通过相图、电子密度与电子迁移率的关系分析表明，反常磁电阻与电子密度之间没有相关性。实验（2）制备了不同铁磁薄膜与二维电子系统之间距离，不同铁磁薄膜尺寸、厚度和形状的GaAs/Al GaAs异质结构样品。结果表明，铁磁薄膜的反常磁电阻与其产生的磁场分布的最小值之间存在着一定的相关性。然而，我们不能一致地解释目前实验的所有结果。