摘要各向异性磁电阻效应是铁磁学中一种经典的磁电阻现象，但在反铁磁中很少 有关于该效应的研究报道。本文中，利用铁磁绝缘体基底 YIG 与反铁磁 IrMn 薄膜， 制备 YIG/IrMn 双层结构的薄膜样品，对反铁磁中的各向异性磁电阻效应进行了初 步探索。实验结果表明，反铁磁在高温与低温下存在两种不同的各向异性磁电阻 效应产生机制，且反铁磁的薄膜厚度可以显著影响该效应。此外，反常（正常） 霍尔效应的探索进一步丰富了 YIG/IrMn 这一薄膜结构的研究内容。由于涉及的理 论知识较为复杂，需要更多的补充实验与理论分析以深入理解其物理本质。68481

毕业论文关键词 反铁磁 各向异性磁电阻 铁磁学 霍尔效应

Title    Anisotropic Magnetoresistance in  Antiferromagnets and Controlling by Electric Field

Abstract

Anisotropic magnetoresistance (AMR) effect is a classic magnetic resistance phenomenon in the field of ferromagnetics. However, there is little research reports concerning the effect in antiferromagnets. In this paper, by using the ferromagnetic insulator YIG and antiferromagnetic film IrMn, the YIG/IrMn double layers sample is prepared. Further, the AMR effect in antiferromagnets is explored preliminarily based on the sample. Results show that there exists two different mechanisms for the occurring of AMR in antiferromagnets under high and low temperature respectively, and the effect can be strongly influenced by the thickness of the antiferromagnetic film. Additionally, the research contents are enriched by means of the exploration on anomalous or ordinary hall effect. Due to the complicated theoretical knowledge involved, more supplementary experiments and theoretical analysis are required to understand the physical nature thoroughly.

Keywords Antiferromagnets Anisotropic Magnetoresistance Ferromagnetics Hall Effect

目 次

1 引言 1

1.1 自旋电子学 1

1.2  各向异性磁电阻效应… 4

1.3  反铁磁… 5

1.4  反铁磁 IrMn 的研究概述… 7

1.5  本论文的研究思路与内容… 9

2 实验原理及方法… 11

2.1  薄膜样品的制备… 11

2.2  薄膜样品霍尔器件的制备… 12

2.3  薄膜样品的结构与成分表征 14

2.4  薄膜样品的磁电性能测试 15

2.5  三种常见的霍尔效应 18

3 磁电阻效应初探及样品表征 22

3.1  铁磁金属的各向异性磁电阻 22

3.2  顺磁性金属的各向异性磁电阻 24

3.3  反铁磁 IrMn 薄膜样品的表征