Enhanced annealing, high Curie temperature and low-voltage gating in (Ga,Mn)As: A surface oxide control study

Abstract

(Ga,Mn)As and related diluted magnetic semiconductors play a major role in spintronics research because of their potential to combine ferromagnetism and semiconducting properties in one physical system. Ferromagnetism requires ~1-10% of substitutional Mn_Ga. Unintentional defects formed during growth at these high dopings significantly suppress the Curie temperature. We present experiments in which by etching the (Ga,Mn)As surface oxide we achieve a dramatic reduction of annealing times necessary to optimize the ferromagnetic film after growth, and report Curie temperature of 180 K at approximately 8% of Mn_Ga. Our study elucidates the mechanism controlling the removal of the most detrimental, interstitial Mn defect. The limits and utility of electrical gating of the highly-doped (Ga,Mn)As semiconductor are not yet established; so far electric-field effects have been demonstrated on magnetization with tens of Volts applied on a top-gate, field effect transistor structure. In the second part of the paper we present a back-gate, n-GaAs/AlAs/GaMnAs transistor operating at a few Volts. Inspired by the etching study of (Ga,Mn)As films we apply the oxide-etching/re-oxidation procedure to reduce the thickness (arial density of carriers) of the (Ga,Mn)As and observe a large enhancement of the gating efficiency. We report gatable spintronic characteristics on a series of anisotropic magnetoresistance measurements.

arXiv comment13 pages, 4 figures

References in corpus (16)

• Theory of ferromagnetic (III,Mn)V semiconductors
• Mn Interstitial Diffusion in (Ga,Mn)As
• Prospects of high temperature ferromagnetism in (Ga,Mn)As semiconductors
• High Curie temperature GaMnAs obtained by resistance-monitored annealing
• Highly enhanced Curie temperatures in low temperature annealed (Ga,Mn)As epilayers
• Self-compensation in manganese-doped ferromagnetic semiconductors
• Anisotropic Magnetoresistance in Ga${}_{1-x}$Mn${}_x$As
• Boltzmann theory of engineered anisotropic magnetoresistance in (Ga,Mn)As
• Determination of the local concentrations of Mn interstitials and antisite defects in GaMnAs
• Capping-induced suppression of annealing in Ga(1-x)Mn(x)As epilayers
• Enhanced annealing effect in an oxygen atmosphere on GaMnAs
• Mn incorporation in as-grown and annealed (Ga,Mn)As layers studied by x-ray diffraction and standing-wave uorescence
• Magnetic and chemical nonuniformity in Ga[1-x]Mn[x]As films as probed by polarized neutron and x-ray reflectometry
• Photoemission studies of the annealing induced modifications of (Ga,Mn)As
• Comment on "Mn Interstitial Diffusion in (Ga,Mn)As"
• Effects of Capping on the (Ga,Mn)As Magnetic Depth Profile

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• Spin-dependent phenomena and device concepts explored in (Ga,Mn)As
• Nonvolatile ferroelectric control of ferromagnetism in (Ga,Mn)As
• A story of high-temperature ferromagnetism in semiconductors
• Structural and paramagnetic properties of dilute Ga1-xMnxN
• Families of magnetic semiconductors -- an overview
• Curie temperature versus hole concentration in field-effect structures of Ga1-xMnxAs
• Chemical trend of exchange couplings in diluted magnetic II-VI semiconductors
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• All electrical measurement of the density of states in (Ga,Mn)As
• Dynamics of diluted magnetic semiconductors from atomistic spin dynamics simulations: Mn doped GaAs as a case study
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• Weak doping dependence of the antiferromagnetic coupling between nearest-neighbor Mn${}^{2+}$ spins in (Ba${}_{1-x}$K${}_x$)(Zn${}_{1-y}$Mn${}_y$)${}_2$As${}_2$
• Diffusion of Mn interstitials in (Ga,Mn)As epitaxial layers
• Interface magnetism and electronic structure: ZnO(0001)/Co3O4(111)
• A semiquantitative approach to the impurity-band-related transport properties of GaMnAs nanolayers
• Establishing micromagnetic parameters of ferromagnetic semiconductor (Ga,Mn)As
• Exchange coupling and Mn valency in GaN doped with Mn and co-doped with Mg
• Mn induced modifications of Ga 3d photoemission from (Ga, Mn)As: evidence for long range effects