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Related papers: Achieving High Curie Temperature in (Ga,Mn)As

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We show that by annealing Ga1-xMnxAs thin films at temperatures significantly lower than in previous studies, and monitoring the resistivity during growth, an unprecedented high Curie temperature Tc and conductivity can be obtained. Tc is…

Materials Science · Physics 2009-11-07 K. W. Edmonds , K. Y. Wang , R. P. Campion , A. C. Neumann , N. R. S. Farley , B. L. Gallagher , C. T. Foxon

We demonstrate that in situ post-growth annealing of GaMnAs layers under As capping is adequate for achieving high Curie temperatures (Tc) in a similar way as ex situ annealing in air or in N2 atmosphere practiced earlier.

Other Condensed Matter · Physics 2009-11-10 M. Adell , V. Stanciu , J. Kanski , L. Ilver , J. Sadowski , J. Z. Domagala , P. Svedlindh , F. Terki , C. Hernandez , S. Charar

We report a clear correspondence between changes in the Curie temperature and carrier density upon annealing in epitaxially grown (Ga,Mn)As layers with thicknesses in the range between 5 nm and 20 nm. The changes are dependent on the layer…

Materials Science · Physics 2009-11-07 B. Sorensen , J. Sadowski , R. Mathieu , P. Svedlindh , P. E. Lindelof

We report Curie temperatures up to 150 K in annealed Ga1-xMnxAs epilayers grown with a relatively low As:Ga beam equivalent pressure ratio. A variety of measurements (magnetization, Hall effect, magnetic circular dichroism and Raman…

We report on an enhancement of the Curie temperature in GaMnAs/InGaMnAs superlattices grown by low-temperature molecular beam epitaxy, which is due to thin InGaMnAs or InGaAs films embedded into the GaMnAs layers. The pronounced increase of…

Materials Science · Physics 2009-11-10 A. Koeder , W. Limmer , S. Frank , W. Schoch , V. Avrutin , R. Sauer , K. Zuern , P. Ziemann , A. Waag

Thin GaMnAs layers grown by molecular beam epitaxy were subjected to low-temperature post growth annealing, with an amorphous arsenic capping layer deposited on the GaMnAs surface directly after the epitaxial growth. It is shown that the…

Materials Science · Physics 2007-05-23 J. Sadowski , J. Z. Domagala , V. Osinniy , J. Kanski , M. Adell , L. Ilver , C. Hernandez , F. Terki , S. Charar , D. Maude

We present the results of low temperature (LT) annealing studies of Ga1-xMnxAs epilayers grown by low temperature molecular beam epitaxy in a wide range of Mn concentrations (0.01<x<0.084). Transport measurements in low and high magnetic…

The effect of annealing at 250 C on the carrier depth profile, Mn distribution, electrical conductivity, and Curie temperature of (Ga,Mn)As layers with thicknesses > 200 nm, grown by molecular-beam epitaxy at low temperatures, is studied by…

Materials Science · Physics 2009-11-11 W. Limmer , A. Koeder , S. Frank , V. Avrutin , W. Schoch , R. Sauer , K. Zuern , J. Eisenmenger , P. Ziemann , E. Peiner , A. Waag

A range of high quality Ga1-xMnxN layers have been grown by molecular beam epitaxy with manganese concentration 0.2 < x < 10%, having the x value tuned by changing the growth temperature (Tg) between 700 and 590 {\deg}C, respectively. We…

We have investigated the effects of post growth low temperature annealing on the magnetic, electrical and structural properties of (Ga_0.94,Mn_0.06)(As_0.9,P_0.1) layers grown by molecular beam epitaxy. By controlling the annealing time we…

The Ga vacancy mediated microstructure evolution of (Ga,Mn)As during growth and post-growth annealing is studied using a multi-scale approach. The migration barriers for the Ga vacancies and substitutional Mn together with their…

Materials Science · Physics 2007-05-23 Hannes Raebiger , Maria Ganchenkova , Juhani von Boehm

(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…

Materials Science · Physics 2009-11-13 K. Olejnik , M. H. S. Owen , V. Novak , J. Masek , A. C. Irvine , J. Wunderlich , T. Jungwirth

We demonstrate the manipulation of the Curie temperature of buried layers of the ferromagnetic semiconductor (Ga,Mn)As using nanolithography to enhance the effect of annealing. Patterning the GaAs-capped ferromagnetic layers into nanowires…

Materials Science · Physics 2009-11-11 K. F. Eid , B. L. Sheu , O. Maksimov , M. B. Stone , P. Schiffer , N. Samarth

We report on a comprehensive combined experimental and theoretical study of Curie temperature trends in (Ga,Mn)As ferromagnetic semiconductors. Broad agreement between theoretical expectations and measured data allows us to conclude that…

The influence of annealing parameters - temperature and time - on the magnetic properties of As-capped (Ga,Mn)As epitaxial thin films have been investigated. The dependence of the transition temperature (Tc) on annealing time marks out two…

Materials Science · Physics 2007-05-23 V. Stanciu , O. Wilhelmsson , U. Bexell , M. Adell , J. Sadowski , J. Kanski , P. Warnicke , P. Svedlindh

Using angle resolved photoemission we have investigated annealing-induced changes in Ga(1-x)Mn(x)As with x = 0.05. We find that the position of the Fermi energy is a function of annealing time and temperature. It is also established that…

Materials Science · Physics 2009-11-10 M. Adell , L. Ilver , J. Kanski , J. Sadowski , R. Mathieu

High- and low-field magneto-transport measurements, as well as SQUID measurements of magnetization, were carried out on Ga1-xMnxAs epilayers grown by low temperature molecular beam epitaxy, and subsequently annealed under various…

Annealing can increase the Curie temperature and net magnetization in uncapped (Ga,Mn)As films, effects that are suppressed when the films are capped with GaAs. Previous polarized neutron reflectometry (PNR) studies of uncapped (Ga,Mn)As…

Materials Science · Physics 2009-11-10 B. J. Kirby , J. A. Borchers , J. J. Rhyne , K. V. O'Donovan , T. Wojtowicz , X. Liu , Z. Ge , S. Shen , J. K. Furdyna

The effect of short-time and long-time annealing at 250C on the conductivity, hole density, and Curie temperature of GaMnAs single layers and GaMnAs/InGaMnAs heterostructures is studied by in-situ conductivity measurements as well as Raman…

Condensed Matter · Physics 2009-11-10 W. Limmer , A. Koeder , S. Frank , M. Glunk , W. Schoch , V. Avrutin , K. Zuern , R. Sauer , A. Waag

Mn-doped GaAs thin films were grown at a high substrate temperature of 580 C. During the growth process, the Mn cell temperature was ramped at different rates, resulting in a variety of different Mn concentration depth profile slopes, as…

Mesoscale and Nanoscale Physics · Physics 2015-02-11 P. Xu , D. Qi , M. L. Ackerman , S. D. Barber , P. M. Thibado
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