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Magnetoresistance Effects (magnetoresistance + effects)

Distribution by Scientific Domains
Physics and Astronomy100%

Selected Abstracts

Transport through (Ga,Mn)As nanoconstrictions

PHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 14 2006
Markus Schlapps
Abstract We investigate magnetoresistance effects for transport across (Ga,Mn)As nanoislands, detached by nanoconstrictions from wider (Ga,Mn)As input leads. As in previous studies a huge magnetoresistance was found for nanoconstrictions in the tunnelling regime. For slightly wider junctions an enhanced anisotropic magnetoresistance effect was observed. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Nernst,Ettingshausen and magnetoresistance effects in Hg1,xCdxSe single crystals in vicinity of phase transitions under hydrostatic pressure

PHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 14 2004
Vladimir V. Shchennikov
Abstract In the present paper the thermomagnetic longitudinal and transverse Nernst,Ettingshausen (N,E) effects were investigated in Hg1,xCdxSe (x = 0.03, 0.07) single crystals at hydrostatic pressure up to ,2 GPa. Substitution of Cd atoms into cation sublattice increases strongly the stability of initial zinc blende lattice and shifts the phase transformation into cinnabar structure to higher pressures P , 1.4 GPa. For ternary Hg1,xCdxSe compounds the values of mobility and scattering parameters of charge carriers have been obtained from the N,E and magnetoresistance (MR) effects up to phase transition points 1.4,1.7 GPa. The decreasing of mobility under pressure is consistent with opening of direct semiconductor gap. In vicinity of the structural phase transformations into cinnabar structure an anomaly of transverse N,E effect was observed connected probably with peculiarity of electronic band structure. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Spin-dependent tunneling in modulated structures of (Ga,Mn)As

PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 2 2007
P. Sankowski
Abstract The spin-dependent tunneling in layered structures based on (Ga,Mn)As, in particular the dependence of the tunneling current on magnetization direction, is studied theoretically. To capture the complexity of the tunneling effects in these semiconductor devices we combine a multi-orbital tight-binding approach with Landauer-Büttiker formalism. This theory allows us to reproduce the tunneling anisotropic magnetoresistance effects observed in (Ga,Mn)As/GaAs Esaki-Zener diodes. The model is also used to describe the in-plane and out-of-plane anisotropy of tunneling magnetoresistance in (Ga,Mn)As-based trilayers. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Co2MnSi as full Heusler alloy ferromagnetic electrode in magnetic tunneling junctions

PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 5 2006
G. Reiss
Abstract The discoveries of antiferromagnetic coupling in Fe/Cr multilayers by Grünberg, the Giant MagnetoResistance by Fert and Grünberg and a large tunneling magnetoresistance at room temperature by Moodera have triggered enormous research on magnetic thin films and magnetoelectronic devices. Large opportunities are especially opened by the spin dependent tunneling resistance, where a strong dependence of the tunneling current on an external magnetic field can be found. In order to obtain large magnetoresistance effects, materials with strongly spin polarized electron gas around the Fermi level have to be found. New materials with potentially 100% spin polarization will be discussed using the example of the full Heusler compound Co2MnSi. First, experimental aspects of the integration of this alloy in magnetic tunneling junctions will be addressed. With these junctions, we obtain up to 100% TMR at low temperature. The current status of this research will then be summarized with special regard to the complex diffusion mechanisms occurring in these devices and to the properties of the interfaces between the Heusler material and the insulator. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]