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The Theoetical Research about the Tunneling Magnetoresistance in Magnetical Tunnel Junctions

Author: ZhangPeiPei
Tutor: XuMing
School: Sichuan Normal University
Course: Condensed Matter Physics
Keywords: Magnetic semiconductor Organic semiconductor Tunneling magnetoresistance Spin-orbit coupling Tunneling coefficient
CLC: O482.5
Type: Master's thesis
Year: 2011
Downloads: 60
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Abstract


The 21st century , science and technology , its rapid development changing people's lives to the transmission and storage of information , the use of electronic charge and spin , this basic research and development of spintronics devices will gradually change the information stored . Compared with traditional magnetic electronics devices , spintronics device is non-volatile , high integration and low power consumption, etc. in the computer read heads , magnetic random access memory (MRAM) shows attractive application prospects. New spintronics material , such as magnetic semiconductors , organic semiconductors have become because of its unique nature to achieve the ideal candidate material for spin polarized transport . Injection and transport properties of the spin polarization in the study of organic semiconductor materials , further understanding of the physical properties of organic semiconductor materials , has important significance to the development of spintronics . This dissertation includes the following two aspects : 1 , select magnetic semiconductor as an intermediate layer , ferromagnetic metal ( FM ) / magnetic semiconductor (FS) / / ferromagnetic metal (FM) / heterojunction spin polarization transport properties . The study showed that: the contrast the general ferromagnetic metal / metal oxide / the ferromagnetic metal sandwich structure , due to the consideration of the spin filter effect of the magnetic semiconductor layers , it can be obtained in the FM / FS / FM tunnel junction greater TMR value . By changing some physical parameters such as the thickness of the magnetic semiconductor layer , Rashba spin - orbit coupling strength , the size of the magnetic molecular field , you can get a reasonable tunneling coefficient and TMR of value. The results of our calculations provide reference for the design of spintronics devices based on the Slonczewski the nearly free electron model , using the transfer matrix method to study the ferromagnetic / layer / organic semiconductor / ferromagnetic three- film tunnel junctions and ferromagnetic metal / insulator / organic semiconductor / ferromagnetic multilayers tunnel junction temperature and bias voltage characteristics of spin-polarized electron tunneling . Limited bias calculated tunneling magnetoresistance (Tunneling MagneticResistance, TMR) with bias and temperature dependence of , also studied at zero temperature tunneling magnetoresistance TMR and the thickness of the insulating layer , the organic semiconductor layer thickness as well as ferromagnetic / organic semiconductor interface potential barrier U of change relationship . The results of our calculations explain the experimental results .

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CLC: > Mathematical sciences and chemical > Physics > Solid State Physics > Solid nature of the > Magnetic properties
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