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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…

High quality strongly correlated two-dimensional (2D) electron systems at low temperatures $T\rightarrow 0$ exhibits an apparent metal-to-insulator transition (MIT) at a large $r_s$ value around 40. We have measured the magnetoresistance of…

Mesoscale and Nanoscale Physics · Physics 2013-07-01 Jian Huang , L. N. Pfeiffer , K. W. West

Photo-excited precession of magnetization in (Ga,Mn)As is investigated by measuring time-resolved magneto-optical response and transient differential reflectivity with pump-and-probe technique. In the time region less than 1 ps, rapidly…

Materials Science · Physics 2014-09-09 T. Matsuda , K. Nishibayashi , H. Munekata

We report accurate energetics of defects introduced in GaN on doping with divalent metals, focussing on the technologically important case of Mg doping, using a model which takes into consideration both the effect of hole localisation and…

We have investigated the room temperature ferromagnetic order that develops in Al-substituted magnesium oxide, Mg(Al)O, nanoparticles with Al fractions of up to 5 at.%. All samples, including undoped MgO nanoparticles, exhibit room…

Materials Science · Physics 2015-06-04 Debabrata Mishra , Balaji P. Mandal , Rupam Mukherjee , Ratna Naik , Gavin Lawes , Boris Nadgorny

Using magnetization measurements, we show that point defects in graphene - fluorine adatoms and irradiation defects (vacancies) - carry magnetic moments with spin 1/2. Both types of defects lead to notable paramagnetism but no magnetic…

Mesoscale and Nanoscale Physics · Physics 2012-05-23 R. R. Nair , M. Sepioni , I-Ling Tsai , O. Lehtinen , J. Keinonen , A. V. Krasheninnikov , T. Thomson , A. K. Geim , I. V. Grigorieva

Present work investigates the structural, electronic and magnetic properties of wurtzite (0001) GaN nanowires (NWs) doped with Gd and point defects by employing the GGA+U approximation. We find that Ga vacancies (VGa) exhibit lower…

Materials Science · Physics 2015-11-09 Assa Aravindh S , Iman S Roqan

The changes that vacancies produce in the properties of hcp solid 4He are studied by means of quantum Monte Carlo methods. Our results show that the introduction of vacancies produces significant changes in the behavior of solid 4He, even…

Other Condensed Matter · Physics 2015-06-04 R. Rota , Y. Lutsyshyn , C. Cazorla , J. Boronat

Proton irradiation of both n-type and semi-insulating bulk samples of \b{eta}-Ga2O3 leads to the formation of one paramagnetic defect with spin S=1/2, monoclinic point symmetry, a g-tensor with principal values of gb=2.0313, gc=2.0079, ga*=…

Kerr rotation and Superconducting QUantum Interference Device (SQUID) magnetometry measurements were performed on ultrathin (Ga$_{0.95}$Mn$_{0.05}$)As layers. The thinner layers (below 250 \AA) exhibit magnetic properties different than…

We study the controlled introduction of defects in GaMnAs by irradiating the samples with energetic ion beams, which modify the magnetic properties of the DMS. Our study focuses on the low-carrier-density regime, starting with as-grown…

Disordered Systems and Neural Networks · Physics 2010-06-14 E. H. C. P. Sinnecker , G. M. Penello , T. G. Rappoport , M. M. Sant'Anna , D. E. R. Souza , M. P. Pires , X. Liu , J. K. Furdyna

Digital alloys of GaSb/Mn have been fabricated by molecular beam epitaxy. Transmission electron micrographs showed good crystal quality with individual Mn-containing layers well resolved; no evidence of 3D MnSb precipitates was seen in…

Materials Science · Physics 2009-11-07 X. Chen , M. Na , M. Cheon , S. Wang , H. Luo , B. D. McCombe , X. Liu , Y. Sasaki , T. Wojtowicz , J. K. Furdyna , S. J. Potashnik , P. Schiffer

The effect of a spatially modulated magnetic field on the weak localization phenomenon in two-dimensional electron gas (2DEG) is studied. Both the dephasing time $\tau_H$ and magnetoresistance are shown to reveal a nontrivial behavior as…

Mesoscale and Nanoscale Physics · Physics 2015-05-14 A. S. Melnikov , S. V. Mironov , S. V. Sharov

Polycrystalline MgB2 samples with GaN additions were prepared by reaction of Mg, B, and GaN powders. The presence of Ga leads to a low melting eutectic phase which allowed liquid phase sintering and produces plate-like grains. For low-level…

Superconductivity · Physics 2009-11-11 S. K. Chen , Z. Lockman , M. Wei , B. A. Glowacki , J. L. MacManus-Driscoll

We study the magnetism in NdFe$_2$Ga$_8$ by the neutron-diffraction and temperature-modulated linear {Gr\"uneisen} parameter measurements. Previous thermodynamical measurements have demonstrated that there are two magnetic transitions at 10…

Strongly Correlated Electrons · Physics 2022-02-14 Xingyu Wang , Cuixiang Wang , Bo Liu , Ke Jia , Xiaoyan Ma , Gang Li , Xiaoping Wang , Chin-Wei Wang , Youguo Shi , Yi-feng Yang , Shiliang Li

In this paper, we report the growth of pure {\alpha}-MoO3 micro-flakes by CVD technique and their structural, electronic, optical, and magnetic properties. Samples are annealed at various temperatures in an H2 atmosphere to induce…

Materials Science · Physics 2023-09-06 Sharmistha Dey , Vikash Mishra , Neetesh Dhakar , Sunil Kumar , Pankaj Srivastava , Santanu Ghosh

The strain of GaN layers grown by Metal Organic Chemical Vapor Deposition (MOCVD) on three vicinal 4H-SiC substrates (0, 3.4 and 8 offcut from [0001] towards [11-20] axis) is investigated by X-ray Diffraction (XRD), Raman Scattering and…

Materials Science · Physics 2007-05-23 Julien Pernot , Etienne Bustarret , Mariusz Rudzinski , Paul R. Hageman , Poul K. Larsen

(MnNiSi)1-(Fe2Ge)x composition (x=0.34) alloy was prepared by arc melting, crushed, and sieved to approximately <32 microns. They were utilized in examining the possible magnetic and structural changes when exposed to a dosage of a…

Materials Science · Physics 2023-03-16 John Peter J. Nunez , Vaibhav Sharma , Jessika V. Rojas , Radhika Barua , Ravi L. Hadimani

A clear gate voltage tunable weak antilocalization and a giant magnetoresistance of 400 percent are observed at 1.9 K in single layer graphene with an out-of-plane field. A large magnetoresistance value of 275 percent is obtained even at…

Materials Science · Physics 2015-06-17 Kalon Gopinadhan , Young Jun Shin , Indra Yudhistira , Jing Niu , Hyunsoo Yang

We analyze Ge-related defects in Ge-doped SiO_2 using first-principles density functional techniques. Ge is incorporated at the level of ~ 1 mol % and above. The growth conditions of Ge:SiO_2 naturally set up oxygen deficiency, with vacancy…

Materials Science · Physics 2009-11-07 C. M. Carbonaro , V. Fiorentini , F. Bernardini