Magnetoopór w tunelowych złączach ferromagnetycznych

Michał Wilczyński

Abstract

Tunneling of the spin-polarized electrons through the single and the double ferromagnetic tunnel junctions of different material configurations is theoretically considered. The tunneling current for different relative orientations of magnetic moments in ferromagnetic components of these junctions and the tunnel magnetoresistance (TMR) are calculated in the case when a finite bias is applied to the junctions. Most of the calculations are made within the framework of extended version of the Slonczewski spin-polarized free-electron-like one-band model. A bias dependence of a barrier height and shape is taken into account. In the case of double barrier systems, sequential and coherent tunneling limits are considered. In the limit of sequential tunneling, an influence of spin accumulation in the central electrode on TMR is analysed. In the coherent tunneling limit, an influence of resonant states on I-V characteristics and TMR is discussed. The variation of the current and TMR with a thickness of the central electrode is investigated. Preliminary results obtained for the double junctions with the central nonmagnetic electrode in the model based on the non-equilibrium Green functions are also presented. In this model the Coulomb interactions in the central electrode are taken into account in the Hartree-Fock approximation. The relationship between the extended Slonczewski model and the model based on equilibrium Green functions is also discussed.
Diploma typeDoctor of Philosophy
Author Michał Wilczyński (FP / SRD)
Michał Wilczyński,,
- Structural Research Division
Title in PolishMagnetoopór w tunelowych złączach ferromagnetycznych
Languagepl polski
Certifying UnitFaculty of Physics (FP)
Disciplinephysics / (physical sciences domain) / (physical sciences)
Defense Date11-10-2001
Supervisor Renata Świrkowicz (FP / SRD)
Renata Świrkowicz,,
- Structural Research Division

Pages165
Keywords in Polishferromagnetyzm, złącza ferromagnetyczne, magnetoopór, zjawiska tunelowania
Abstract in EnglishTunneling of the spin-polarized electrons through the single and the double ferromagnetic tunnel junctions of different material configurations is theoretically considered. The tunneling current for different relative orientations of magnetic moments in ferromagnetic components of these junctions and the tunnel magnetoresistance (TMR) are calculated in the case when a finite bias is applied to the junctions. Most of the calculations are made within the framework of extended version of the Slonczewski spin-polarized free-electron-like one-band model. A bias dependence of a barrier height and shape is taken into account. In the case of double barrier systems, sequential and coherent tunneling limits are considered. In the limit of sequential tunneling, an influence of spin accumulation in the central electrode on TMR is analysed. In the coherent tunneling limit, an influence of resonant states on I-V characteristics and TMR is discussed. The variation of the current and TMR with a thickness of the central electrode is investigated. Preliminary results obtained for the double junctions with the central nonmagnetic electrode in the model based on the non-equilibrium Green functions are also presented. In this model the Coulomb interactions in the central electrode are taken into account in the Hartree-Fock approximation. The relationship between the extended Slonczewski model and the model based on equilibrium Green functions is also discussed.
Thesis file
Wilczynski_Michal_magnetoopor.pdf 4.21 MB
Citation count*4 (2015-07-23)

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