Anisotropic Magnetoresistance components in (Ga,Mn)As

Abstract

Our experimental and theoretical study of the non-crystalline and crystalline components of the anisotropic magnetoresistance (AMR) in (Ga,Mn)As is aimed at exploring the basic physical aspects of this relativistic transport effect. The non-crystalline AMR reflects anisotropic lifetimes of the holes due to polarized Mn impurities while the crystalline AMR is associated with valence band warping. We find that the sign of the non-crystalline AMR is determined by the form of spin-orbit coupling in the host band and by the relative strengths of the non-magnetic and magnetic contributions to the impurity potential. We develop experimental methods directly yielding the non-crystalline and crystalline AMR components which are then independently analyzed. We report the observation of an AMR dominated by a large uniaxial crystalline component and show that AMR can be modified by local strain relaxation. We discuss generic implications of our experimental and theoretical findings including predictions for non-crystalline AMR sign reversals in dilute moment systems.

4 pages, 3 figures. Phys. Rev. Lett. in press

References in corpus (4)

• Theory of ferromagnetic (III,Mn)V semiconductors
• On the character of states near the Fermi level in (Ga,Mn)As: impurity to valence band crossover
• Angle-dependent magnetotransport in cubic and tetragonal ferromagnets: Application to (001)- and (113)A-oriented (Ga,Mn)As
• Lithographic engineering of anisotropies in (Ga,Mn)As

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• Advanced resistivity model for arbitrary magnetization orientation applied to a series of compressive- to tensile-strained (Ga,Mn)As layers
• An extensive comparison of anisotropies in MBE grown (Ga,Mn)As material
• Low voltage control of ferromagnetism in a semiconductor p-n junction
• Microscopic mechanism of the non-crystalline anisotropic magnetoresistance in (Ga,Mn)As
• Valence band orbital polarization in III-V ferromagnetic semiconductors
• Nonvanishing anisotropic magnetoresistance in Rashba two-dimensional electron systems with nonmagnetic disorders
• Huge tunnelling anisotropic magnetoresistance in (Ga,Mn)As nanoconstrictions