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1.
磁电子学中的若干问题   总被引:32,自引:0,他引:32  
本文综述了自旋极化输运过程中巡游电子的自旋极化、自旋相关的散射及自旋弛豫等三方面的内容;全面总结了铁磁金属的磁电阻效应(AMR)、磁性金属多层膜和颗粒膜的巨磁电阻效应(GMR)、氧化物铁磁体的特大磁电阻效应(CMR)以及磁隧道结的巨大隧道电阻效应(TMR)研究中具有代表性的实验结果及理论模型;简单介绍了新生的磁电子器件—磁电阻型随机存取存储器(MRAM)和全金属自旋晶体管的工作原理和工作过程。  相似文献   

2.
姚志  孙继忠  李建东 《物理实验》2012,32(4):5-8,16
测量了不同方向外磁场和温度下多层膜巨磁电阻的磁阻特性,给出了巨磁电阻模拟传感器用于电流测量的最佳磁偏置.结果表明:外磁场强度相同但方向不同,对巨磁电阻的作用效果不同,巨磁电阻饱和时,阻值与外磁场方向无关.温度不同,巨磁电阻的阻值不同,磁电阻变化率也有改变.  相似文献   

3.
多层膜的巨磁电阻   总被引:14,自引:0,他引:14  
翟宏如  鹿牧 《物理学进展》1997,17(2):159-179
本文总结了多层膜中巨磁电阻的物理机制及其研究进展。为了对多层膜磁电阻的各个可能来源有全面的认识,首先简述了正常磁电阻和各向异性磁电阻的原理,然后在本文的主要部分,着重介绍了铁磁金属和多层膜中的自旋相关散射与双电流模型及在多层膜巨磁电阻基础研究和材料研究领域的进展,列举出具有巨磁电阻的各种多层结构。最后报道了巨磁电阻的主要应用。  相似文献   

4.
自旋输运和巨磁电阻--自旋电子学的物理基础之一   总被引:15,自引:1,他引:14  
邢定钰 《物理》2005,34(5):348-361
介绍磁性纳米结构和锰氧化物中电子的自旋极化输运和巨磁电阻效应,它们是新近发展的自旋电子学的物理基础之一.着重讨论的是以下三方面的基本物理图像:磁多层结构的巨磁电阻,铁磁隧道结的隧穿磁电阻,掺杂锰氧化物的庞磁电阻效应.  相似文献   

5.
磁电子学器件应用原理   总被引:13,自引:0,他引:13  
蔡建旺 《物理学进展》2006,26(2):180-227
本文介绍几种重要的磁电子器件的基本结构和工作原理,包括巨磁电阻与隧穿磁电阻传感器、巨磁电阻隔离器、巨磁电阻与隧穿磁电阻硬盘读出磁头、磁电阻随机存取存储器、自旋转移磁化反转与微波振荡器。自旋晶体管作为未来磁电子学或自旋电子学时代的基本元素,目前大都还处在概念型阶段,本文也将对几种自旋晶体管的大致原理作简要介绍。  相似文献   

6.
蔡建旺 《物理学进展》2011,26(2):180-227
本文介绍几种重要的磁电子器件的基本结构和工作原理,包括巨磁电阻与隧穿磁电阻传感器、巨磁电阻隔离器、巨磁电阻与隧穿磁电阻硬盘读出磁头、磁电阻随机存取存储器、自旋转移磁化反转与微波振荡器。自旋晶体管作为未来磁电子学或自旋电子学时代的基本元素,目前大都还处在概念型阶段,本文也将对几种自旋晶体管的大致原理作简要介绍。  相似文献   

7.
磁电阻效应的研究进展   总被引:19,自引:3,他引:16  
介绍了磁电阻效应的研究状况和进展,总结了铁磁金属的磁电阻效应、磁性多层膜和颗粒膜的巨磁阻效应、磁隧道电阻效应及氧化物铁磁体的超大磁阻效应的理论模型,并简要分析了磁电阻效应的物理机制。  相似文献   

8.
许小勇  钱丽洁  胡经国 《物理学报》2009,58(3):2023-2029
通过研究外应力场下铁磁多层膜系统中的自旋结构,讨论了系统磁电阻对外应力的依赖关系.结果表明,外应力能够诱发磁电阻效应,且其磁电阻紧密依赖于外应力的大小和方向.一般地对铁磁性层间耦合,其磁电阻与外应力之间的关系紧密地依赖于两铁磁层的磁致伸缩系数以及磁晶各向异性之差异.具体地,大小一定的外应力由磁易轴向磁难轴旋转的过程中,磁电阻先缓慢增大后急剧减小,在磁难轴附近变化较敏锐,并出现峰值.外应力方向一定时,磁电阻随应力的增大先敏锐增强后缓慢减小,且应力方向偏离磁易轴越远,变化趋势越显著.特别地,当外应力完全垂直于磁易轴时,应力大小的变化会引起磁电阻翻倍.而外应力场介于8πM/5≤Hλ≤18πM/5时,磁电阻会随应力的旋转单调上升,并在磁难轴附近急剧增强,产生GMR效应;对反铁磁性层间耦合,其GMR效应对应力大小和方向的响应近似地相反于铁磁性层间耦合情形. 关键词: 铁磁/非磁/铁磁三层膜 自旋结构 磁电阻 应力场  相似文献   

9.
温戈辉  蔡建旺 《物理》1997,26(11):690-693,642
简要回顾了利用量子隧道效应测定铁磁金属传导电子自旋极化率的研究历史,综述了自旋极化电子隧穿产应导致的“铁磁金属/非磁绝缘体/铁磁金属”三层平面型隧道结中的巨磁电阻效应以及“铁磁金属/非磁绝缘体”颗粒膜系统中的隧穿类型巨磁电阻效应的研究进展。  相似文献   

10.
本文总结了多层膜中巨磁电阻的物理机制及其研究进展。为了对多层膜磁电阻的各个可能来源有全面的认识,首先简述了正常磁电阻和各向异性磁电阻的原理,然后在本文的主要部分,着重介绍了铁磁金属和多层膜中的自旋相关散射与双电流模型及在多层膜巨磁电阻基础研究和材料研究领域的进展,列举出具有巨磁电阻的各种多层结构。最后报道了巨磁电阻的主要应用。  相似文献   

11.
The contribution of spin-polarized electrons, injected from a ferromagnet to a polymer, to the giant magnetoresistance has been investigated for the ferromagnet-polymer-nonmagnetic metal system. It is established that, at complete depolarization of injected electrons, magnetic field does not affect the conductivity of the system. The electric field effect (significant decrease in the threshold magnetic field) on the parameters of giant injection magnetoresistance is established.  相似文献   

12.
The theoretical and experimental studies of the giant magnetoresistance effect in metallic magnetic multilayers with measuring current perpendicular to the interface planes are reviewed. Theoretical formalisms of electronic transport in the inhomogeneous electron gas are critically compared with emphasis on the perpendicular magnetoresistance in multilayers. The effects of interface roughness, potential steps at the interfaces, and realistic band structures are addressed. The experimental determination of the perpendicular resistance of metallic multilayers requires either low-resistance measurement techniques or microfabricated samples with enhanced resistances. The experimental methods known at present are discussed and, where possible, compared with each other.  相似文献   

13.
The functional dependence of the giant magnetoresistance (GMR) with respect to the relative angle between the orientations of the magnetization in the magnetic slabs of a trilayer system is calculated by using the Kubo-Greenwood formula for electrical transport together with the fully-relativistic spin-polarized screened Korringa-Kohn-Rostoker method for semi-infinite systems and the coherent potential approximation. It is found that the functional dependence of the GMR is essentially of the form . Received 30 November 1998  相似文献   

14.
Nathan Wiser 《Physica A》1993,200(1-4):770-776
A discussion is presented of the effect of interface scattering on the giant magnetoresistance of magnetic multilayers. It has recently been found experimentally that increased interface scattering causes the magnetoresistance to increase for Fe/Cr multilayers, but to decrease for Co/Cu multilayers. An explanation is proposed for this striking difference in behaviour for these two systems.  相似文献   

15.
利用巨磁电阻传感器设计了多功能测量仪器,实验表明该测量仪能够精确测量物体的转速和转角,直观地演示行驶车辆对地磁场的扰动.  相似文献   

16.
The problem of conductivity of a multilayer sample (alternating magnetic and nonmagnetic metal layers) with a current parallel to its surfaces is solved using a set of kinetic equations. Conditions at which the conductivity variations associated with changes in the type of magnetization alignment in adjacent layers reach the values on the order of initial conductivity are considered. Parameters governing the giant magnetoresistance effect and the relations between them are determined.  相似文献   

17.
A giant magnetoresistance, reaching 74% in a magnetic field of 38 T at 3 K, was observed in the CuCr1.6Sb0.4S4 semiconductor spinel. The magnetic properties point to the existence of a magnetic two-phase state in this compound. The giant magnetoresistance was explained by the existence of the magnetic two-phase state due to strong s-d exchange.  相似文献   

18.
We show for a simple d-band TB Hamiltonian that noncollinear magnetic configurations can contribute to large inverse giant magnetoresistance (IGMR) ratios. We make a systematic study as a function of band filling, magnetic moment and canting angle for some simple model examples and use the outcome of this study to interpret the experimentally observed IGMR ratios on LaMn2Ge2.  相似文献   

19.
Effect of interface number on giant magnetoresistance   总被引:1,自引:0,他引:1  
Ni(Cu)/Cu, Co(Cu)/Cu, and Ni-Co(Cu)/Cu multilayers with a varied number of interfaces (i.e. bi-layers) were electrodeposited on gold coated quartz discs in a flow channel cell by a potentiostatic dual-pulse plating method. It was found that the giant magnetoresistance of these multilayers increased almost linearly with increase in the number of interfaces. This result confirms that the interfaces play a dominating role in giant magnetoresistance. Comparable samples of these three types of multilayers were prepared under identical electrochemical conditions from appropriate baths. The result showed that Ni-Co(Cu)/Cu multilayers exhibited much higher giant magnetoresistance than Ni(Cu)/Cu, and Co(Cu)/Cu multilayers, which was possibly due to the structural differences between the multilayers.  相似文献   

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