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Considerable efforts have been devoted recently to synthesize diluted magnetic semiconductors having ferromagnetic properties at room temperature because of their technological impacts for spintronic devices. In 2001 successful growth of…

We report on Gd ion implantation and magnetic characterization of GaN films on sapphire substrates and of bare sapphire and Si substrates to shed light on the mechanism underlying the induced magnetism upon Gd ion implantation. For all…

Materials Science · Physics 2011-03-29 X. Wang , C. Timm , X. M. Wang , W. K. Chu , J. Y. Lin , H. X. Jiang , J. Z. Wu

Wurtzite GaN:Mn films on sapphire substrates were successfully grown by use of the molecular beam epitaxy (MBE) system. The film has an extremely high Curie temperature of around 940 K, although the Mn concentration is only about 3 ~ 5 %.…

Materials Science · Physics 2009-11-07 H. Hori , S. Sonoda , T. Sasaki , Y. Yamamoto , S. Shimizu , K. Suga , K. Kindo

We present an explanation of recently observed giant magnetic moment and room-temperature ferromagnetism in the dielectric GaN doped with Gd. Our approach uses the polarization mechanism of exchange interaction, which occurs if the d-level…

Materials Science · Physics 2015-05-13 V. I. Litvinov , V. K. Dugaev

Clear evidence of ferromagnetic behavior at temperatures >400 K as well as spin polarization of the charge carriers have been observed in ZnMnO thin films grown on Al2O3 and MgO substrates. The magnetic properties depended on the exact Mn…

The microscopic magnetic properties of high-quality GdN thin films have been investigated by electron spin resonance (ESR) and ferromagnetic resonance (FMR) measurements. Detailed temperature dependence ESR measurements have shown the…

We present a detailed study of the magnetic properties of low-temperature-molecular-beam-epitaxy grown Ge:Mn dilute magnetic semiconductor films. We find strong indications for a frozen state of Ge_{1-x}Mn_{x}, with freezing temperatures of…

Materials Science · Physics 2007-05-23 C. Jaeger , C. Bihler , T. Vallaitis , S. T. B. Goennenwein , M. Opel , R. Gross , M. S. Brandt

A new scenario of the mechanism of intriguing ferromagnetic properties in Mn-doped magnetic semiconductor (Ga,Mn)As is examined in detail. We find that magnetic features seen in zero-field cooled and field cooled magnetizations are not…

Materials Science · Physics 2009-11-11 K. Hamaya , T. Koike , T. Taniyama , T. Fujii , Y. Kitamoto , Y. Yamazaki

We report on unusual magnetic properties observed in the nanofluid room-temperature ferromagnetic graphite (with an average particle size of l=10nm). More precisely, the measured magnetization exhibits a low-temperature anomaly (attributed…

Periodic structures of GdN particles encapsulated in a single crystalline GaN matrix were prepared by plasma assisted molecular beam epitaxy. High resolution X-ray diffractometery shows that GdN islands, with rock salt structure are…

Materials Science · Physics 2012-04-18 T. F. Kent , J. Yang , L. Yang , M. J. Mills , R. C. Myers

Occurrence of room temperature ferromagnetism is demonstrated in pulsed laser deposited thin films of Sn1-xCoxO2-d (x<0.3). Interestingly, films of Sn0.95Co0.05O2-d grown on R-plane sapphire not only exhibit ferromagnetism with a Curie…

We report on a monotonic reduction of Curie temperature in dilute ferromagnetic semiconductor (Ga,Mn)As upon a well controlled chemical-etching/oxidizing thinning from 15 nm down to complete removal of the ferro- magnetic response. The…

Materials Science · Physics 2012-06-29 O. Proselkov , D. Sztenkiel , W. Stefanowicz , M. Aleszkiewicz , J. Sadowski , T. Dietl , M. Sawicki

We report measurements of the optical gap in a GdN film at temperatures from 300 to 6K, covering both the paramagnetic and ferromagnetic phases. The gap is 1.31eV in the paramagnetic phase and red-shifts to 0.9eV in the spin-split bands…

Strongly Correlated Electrons · Physics 2009-11-13 H. J. Trodahl , A. R. H. Preston , J. Zhong , B. J. Ruck , N. Strickland , C. Mitra , W. R. L. Lambrecht

Two-dimensional (2D) magnetic van der Waals materials provide a powerful platform for studying fundamental physics of low-dimensional magnetism, engineering novel magnetic phases, and enabling ultrathin and highly tunable spintronic…

We examine the Mn concentration dependence of the electronic and magnetic properties of optimally annealed Ga1-xMnxAs epilayers for 1.35% < x < 8.3%. The Curie temperature (Tc), conductivity, and exchange energy increase with Mn…

Condensed Matter · Physics 2009-11-07 S. J. Potashnik , K. C. Ku , R. Mahendiran , S. H. Chun , R. F. Wang , N. Samarth , P. Schiffer

We have studied magnetic properties of heavily Mn-doped [(In0.44Ga0.56)0.79Mn0.21]As thin films grown by low-temperature molecular-beam epitaxy (LT-MBE) on InP substrates. The (InGaMn)As with high Mn content (21%) was obtained by decreasing…

Materials Science · Physics 2009-11-10 Shinobu Ohya , Hideo Kobayashi , Masaaki Tanaka

We report on a comprehensive study of the ferromagnetic moment per Mn atom in (Ga,Mn)As ferromagnetic semiconductors. Theoretical discussion is based on microscopic calculations and on an effective model of Mn local moments…

Since 2000, the intensive effort in materials research to develop a diluted magnetic semiconductor exhibiting high-temperature (HT) ferromagnetism above room temperature was not successful. Here, the possible first bulk diluted…

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…

We report on the metalorganic chemical vapor deposition (MOCVD) of GaN:Fe and (Ga,Fe)N layers on c-sapphire substrates and their thorough characterization via high-resolution x-ray diffraction (HRXRD), transmission electron microscopy…

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