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Single planar arrays of Ga(x)Fe(4-x)N magnetic nanocrystals embedded in GaN have been fabricated in an epitaxial process. The phase of the nanocrystals and their epitaxial relationship with the host matrix are studied $via$ high-resolution…

材料科学 · 物理学 2015-06-11 A. Navarro-Quezada , T. Devillers , Tian Li , A. Bonanni

We have prepared the dilute magnetic semiconductor (DMS) InMnAs with different Mn concentrations by ion implantation and pulsed laser melting. The Curie temperature of the In1-xMnxAs epilayer depends on the Mn concentration x, reaching 82 K…

材料科学 · 物理学 2015-06-05 Y. Yuan , Y. Wang , K. Gao , M. Khalid , C. Wu , W. Zhang , F. Munnik , E. Weschke , C. Baehtz , W. Skorupa , M. Helm , S. Zhou

Ion implantation of Mn combined with pulsed laser melting is employed to obtain two representative compounds of dilute ferromagnetic semiconductors (DFSs): Ga1-xMnxAs and In1-xMnxAs. In contrast to films deposited by the widely used…

While achieving high Curie temperatures (above room temperature) in diluted magnetic semiconductors remains a challenge in the case of well controlled homogeneous alloys, several systems characterized by a strongly inhomogeneous…

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…

凝聚态物理 · 物理学 2009-11-10 W. Limmer , A. Koeder , S. Frank , M. Glunk , W. Schoch , V. Avrutin , K. Zuern , R. Sauer , A. Waag

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…

材料科学 · 物理学 2009-11-10 M. Adell , L. Ilver , J. Kanski , J. Sadowski , R. Mathieu

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…

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…

材料科学 · 物理学 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

We report the results of a detailed study of the structural, magnetic and magnetotransport properties of as-grown and annealed Ga0.91Mn0.09As thin films grown on (311)A and (311)B GaAs substrates. The high Curie temperature and hole density…

材料科学 · 物理学 2009-11-11 K. Y. Wang , K. W. Edmonds , L. X. Zhao , M. Sawicki , R. P. Campion , B. L. Gallagher , C. T. Foxon

We report synthesis of single crystalline NaMnAs, confirm its antiferromagnetic order and characterise the sample by photoemission spectroscopy. The electronic structure was studied using optical transmittance, x-ray and ultraviolet…

The phase transition near 40~$^{\circ }$C of both as-grown thin epitaxial MnAs films prepared by molecular beam epitaxy on GaAs(001) and nanometer-scale disks fabricated from the same films is studied. The disks are found to exhibit a…

介观与纳米尺度物理 · 物理学 2019-07-17 B Jenichen , Y Takagaki , K H Ploog , N Darowski , R Feyerherm , I Zizak

Magnetic properties of MnAs were studied as a function of temperature with a superconducting interference device (5 K to 350 K), and atomic force microscopy/magnetic force microscopy (20 K to 360 K). Structural and magnetic properties of…

材料科学 · 物理学 2007-05-23 M. Cheon , S. Hegde , S. Wang , M. M. Bishara , G. B. Kim , H. Luo

We investigated the thermal evolution of the magnetic properties of MnAs epitaxial films grown on GaAs(001) during the coexistence of hexagonal/orthorhombic phases using polarized resonant (magnetic) soft X-ray scattering and magnetic force…

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…

材料科学 · 物理学 2009-11-07 B. Sorensen , J. Sadowski , R. Mathieu , P. Svedlindh , P. E. Lindelof

We report on detailed investigations of the electronic and magnetic properties of ferromagnetic GaMnAs layers, which have been fabricated by low-temperature molecular-beam epitaxy. Superconducting quantum interference device measurements…

Growth of GaMnAs by molecular beam epitaxy is typically performed at low substrate temperatures (250C) and high As overpressures leading to the incorporation of excess As and Mn interstitials, which quench optical signals such as…

材料科学 · 物理学 2009-09-29 M. Poggio , R. C. Myers , N. P. Stern , A. C. Gossard , D. D. Awschalom

First principles total-energy pseudopotential calculations have been performed to investigate STM images of the (110) cross-sectional surface of Mn-doped GaAs. We have considered configurations with Mn in interstitial positions in the…

材料科学 · 物理学 2007-05-23 A. Stroppa

Voids adjacent to both cubic (ZnS-type) and hexagonal (NiAs-type) Mn-rich nanocrystals are characterized using aberration-corrected transmission electron microscopy in annealed Ga0.995Mn0.005As magnetic semiconductor specimen grown by…

材料科学 · 物理学 2015-05-27 A. Kovacs , J. Sadowski , T. Kasama , J. Domagala , R. Mathieu , T. Dietl , 5 , R. E. Dunin-Borkowski

We investigate half-metallicity in [001] stacked (CrAs)$_n$/(GaAs)$_n$ heterostructures with $n \leq 3$ by means of a combined many-body and electronic structure calculation. Interface states in the presence of strong electronic…

材料科学 · 物理学 2015-05-20 L. Chioncel , I. Leonov , H. Allmaier , F. Beiuseanu , E. Arrigoni , T. Jurcut , W. Pötz

We complete our earlier (Phys. Rev. B, {\bf 66}, 134435 (2002)) study of the electronic structure, exchange interactions and Curie temperature in (GaMn)As and extend the study to two other diluted magnetic semiconductors (GaCr)As and…

材料科学 · 物理学 2009-11-10 L. M. Sandratskii , P. Bruno