自旋阀中的极化输运与相关自旋新材料及结构研究  

Study on spin-dependent transport in spin valve and new spintronic materials and structures

作　　者：唐晓莉[1] 张怀武[1] 

机构地区：[1]电子科技大学电子薄膜与集成器件国家重点实验室,四川成都610054

出　　处：《电子元件与材料》2008年第7期70-71,共2页Electronic Components And Materials

基　　金：国家自然科学基金资助项目(No.90306015)

摘　　要：电子既是电荷的载体又是自旋的载体。电子作为电荷的载体，使二十世纪成为了微电子学的天下。而随着1988年巨磁电阻（GMR）效应发现以来，通过操纵电子的另一量子属性——自旋，使新一代的电子器件又多了一维控制手段。电子自旋的研究涵盖了金属磁性多层膜、磁性氧化物、磁性半导体等众多体系，探寻这些体系中自旋输运的基本原理是研究，的重点。目前，基于传统自旋阀中极化输运及自旋电子学的发展，对新材料和新结构的研究尚不成熟，还有众多科学问题亟待解决，诸如：如何在室温下获得更大的巨磁电阻变化率、提高器件的稳定性及灵敏度、自旋阀中交换偏置场产生的物理根源、实现自旋同半导体完美结合的材料、结构及方法等。因此，基于国内外自旋电子学研究的重点，首先围绕最基本的自旋阀纳米多层膜结构，开展了自旋阀多层膜制备、设计、结构优化、自旋阀交换偏置核心结构物理机制探索等研究；其次，提出了三种异质结新结构，并以大自旋极化率Fe3O4磁性半金属为核心材料，开展了自旋阀、新异质结研究；最后，在理论与材料研究的基础上，对自旋器件进行了设计与实验研究，获得了一些有益的结果：（1）理论方面，基于自旋电子器件进一步发展对新结构、新材料发展的需求，提出了磁性半导体，半导体、磁性半导体，磁性半导体、自旋滤波材料，自旋滤波材料的新自旋异质结模型。理论分析发现，利用磁性半导体，半导体异质结，在负偏压的作用下可实现自旋电子的极化输运，而利用磁性半导体，磁性半导体、自旋滤波材料／自旋滤波材料异质结可实现趋于100％的磁电阻变化率。另外通过计算，对可实现的磁阻效应及对材料的要求进行了详细研究，为新材料的应用奠定了一定的理论基础。（2）虽Electrons are tiny magnets as well as elementary charged particles. The electron acting as charge makes the last half of the 20^th century be called the microelectronics era. Since the discovery of giant magnetoresistance （GMR） effect in 1988, by incorporating one of these quantum effects, electron spin, into device design, spintronics offers a new dimension to the practice of electronics. The approach to spintronics is very broad and includes the investigation of spin dependent processes in various systems ranging from metallic multilayers via oxide magnets to semiconductors. At present, there are numerous issues which are needed to solve, based on spin-depentent transport in spin valve （SV） and satisfied with the requiring of new material and structure for spintronics, such as achievement large GMR, improving stability and sensitivity, understanding of microscopic origin of exchange bias phenomenon, finding the new materials, structures and methods for combining ferromagnets and semiconductors, etc. Design, fabrication, optimized structures of SV and exchange bias were researched. Furthermore, three kinds of new heterojuctions for spin-dependent transport were proposed and theoretically analyzed. In addition, based on the research of magnetic half-metallic Fe3O4, the SV and Fe3O4/n-Si heterojuction were investigated. The major results are summarized as follows： （1） Following the development of spintronic devices, ferromagnetic semiconductors/normal semiconductors, ferromagnetic semiconductors/ ferromagnetic semiconductors and spin filter I/spin filter II hybrid junctions are proposed and theoretically analyzed. Theoretical calculations of these junctions show that spin-dependent transport can be realized in ferromagnetic semiconductors/normal semiconductors junction when a reversal bias voltage is applied. In addition, adopting ferromagnetic semiconductors/ferromagnetic semiconductors and spin filter I/spin filter II hybrid junctions a large magnetoresistance nearly 100% can be

关 键 词：电子技术 自旋极化输运 自旋阀 巨磁电阻效应 交换偏置 Fe3O4磁性半金属 

分 类 号：TN4[电子电信—微电子学与固体电子学]