Stoichiometric growth of high Curie temperature heavily alloyed GaMnAs

Mack, Shawn; Myers, Roberto C.; Heron, John T.; Gossard, A. C.; Awschalom, D. D.

doi:10.1063/1.2927481

Cited by 62 publications

(57 citation statements)

References 20 publications

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“…This model predicts an increase of Curie temperature with increasing Mn concentration. However, as it was shown, e.g., by Mack et al, 5 the increased Mn content did not raise Curie temperature. At present, the highest observed Curie temperature for (Ga,Mn)As thin films is about 180 K, 6 which is still far from the room temperature.…”

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confidence: 70%

Ferromagnetic (Ga,Mn)As nanowires grown by Mn-assisted molecular beam epitaxy

Bouravleuv

Cirlin

Sapega³

et al. 2013

Journal of Applied Physics

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(Ga,Mn)As nanowires were grown by molecular beam epitaxy using Mn as a growth catalyst on GaAs(001) substrates at 485 °C, i.e., at intermediate temperatures higher than ones used for the growth of (Ga,Mn)As thin films, but lower than the ordinary temperatures of Au-assisted growth of GaAs nanowires. (Ga,Mn)As nanowires obtained with typical lengths between 0.8 and 4 μm and diameters 50–90 nm do not have defects, such as dislocations or precipitates, except for the stacking faults lying parallel to the growth direction. The investigation of magnetic and optical properties has been carried out not only for as-grown samples with nanowires but also for peeled off nanowires from the host substrate. The results obtained demonstrate that (Ga,Mn)As nanowires exhibit ferromagnetic ordering around 70 K.

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confidence: 70%

Ferromagnetic (Ga,Mn)As nanowires grown by Mn-assisted molecular beam epitaxy

Bouravleuv

Cirlin

Sapega³

et al. 2013

Journal of Applied Physics

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“…Inferring doping trends in basic material properties of (Ga,Mn)As from sample series mixing as-grown and annealed materials, as has been often the case in the literature 7,9 , is unsuitable as the quality of the samples may vastly vary in such a series. Chosing one a priori-fixed T G , T A and annealing time for a range of Mn dopings, as is also common in the literature 7,9,16,17 , is unlikely to produce a high-quality, uniform and uncompensated (Ga,Mn)As material even for one of the considered dopings and is bound to produce lower quality samples for most of the studied Mn dopings. Finally, reliable measurements of intrinsic semiconducting and magnetic properties on optimized (Ga,Mn)As samples require exceedingly long annealing times for film thicknesses \50 nm and are unachievable in B100 nm and thicker films by the known approaches to the (Ga,Mn)As epilayer synthesis.…”

Section: Resultsmentioning

confidence: 99%

The essential role of carefully optimized synthesis for elucidating intrinsic material properties of (Ga,Mn)As

et al. 2013

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(Ga,Mn)As is at the forefront of spintronics research exploring the synergy of ferromagnetism with the physics and the technology of semiconductors. However, the electronic structure of this model spintronics material has been debated and the systematic and reproducible control of the basic micromagnetic parameters and semiconducting doping trends has not been established. Here we show that seemingly small departures from the individually optimized synthesis protocols yield non-systematic doping trends, extrinsic charge and moment compensation, and inhomogeneities that conceal intrinsic properties of (Ga,Mn)As. On the other hand, we demonstrate reproducible, well controlled and microscopically understood semiconducting doping trends and micromagnetic parameters in our series of carefully optimized epilayers. Hand-in-hand with the optimization of the material synthesis, we have developed experimental capabilities based on the magneto-optical pumpand-probe method that allowed us to simultaneously determine the magnetic anisotropy, Gilbert damping and spin stiffness constants from one consistent set of measured data.

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“…The films were prepared using the non-rotated, low-temperature growth techniques reported in Refs. 19,39 . Since this study involved several doping regimes, details of the growth vary between samples.…”

Section: A Sample Growth and Characteristicsmentioning

confidence: 99%

Ferromagnetism and infrared electrodynamics of Ga1−xMnxAs

et al. 2013

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We report on the magnetic and the electronic properties of the prototype dilute magnetic semiconductor Ga1−xMnxAs using infrared (IR) spectroscopy. Trends in the ferromagnetic transition temperature TC with respect to the IR spectral weight are examined using a sum-rule analysis of IR conductivity spectra. We find non-monotonic behavior of trends in TC with the spectral weight to effective Mn ratio, which suggest a strong double-exchange component to the FM mechanism, and highlights the important role of impurity states and localization at the Fermi level. Spectroscopic features of the IR conductivity are tracked as they evolve with temperature, doping, annealing, As-antisite compensation, and are found only to be consistent with an Mn-induced IB scenario. Furthermore, our detailed exploration of these spectral features demonstrates that seemingly conflicting trends reported in the literature regarding a broad mid-IR resonance with respect to carrier density in Ga1−xMnxAs are in fact not contradictory. Our study thus provides a consistent experimental picture of the magnetic and electronic properties of Ga1−xMnxAs.

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Stoichiometric growth of high Curie temperature heavily alloyed GaMnAs

Cited by 62 publications

References 20 publications

Ferromagnetic (Ga,Mn)As nanowires grown by Mn-assisted molecular beam epitaxy

Ferromagnetic (Ga,Mn)As nanowires grown by Mn-assisted molecular beam epitaxy

The essential role of carefully optimized synthesis for elucidating intrinsic material properties of (Ga,Mn)As

Ferromagnetism and infrared electrodynamics of Ga1−xMnxAs

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