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- 1. J.Am.Chem.Soc. 130, 48 (2008) , ACS , “Enhanced Ferromagnetism and Tunable Saturation Magnetization of Mn/C Codoped GaN Nanostructures Synthesized by Carbothermal Nitridation”, Zeyan Wang, Baibiao Huang, Lin Yu, Ying Dai, Peng Wang, Xiaoyan Qin, Xiaoyang Zhang, Jiyong Wei, Jie Zhan, Xiangyang Jing, Haixia Liu, and Myung-Hwan WhangboMn/C-codoped GaN nanostructures were synthesized by carbothermal nitridation with active charcoal as the carbon source. Nanostructures such as zigzag nanowires and nanoscrews were observed by varying the reaction time and the C/Ga molar ratio of the starting material used for the synthesis. The structures and morphologies of the as-grown samples were characterized by X-ray diffraction, scanning electron microscopy, and high-resolution transmission electron microscopy measurements. The doping of both Mn and C in the GaN matrix was confirmed by X-ray photoelectron spectroscopy measurements, and the ferromagnetic properties of Mn/C-codoped GaN samples were confirmed by room-temperature magnetization measurements. The saturation magnetization of Mn/C-codoped GaN increases steadily with increasing C/Ga molar ratio of the starting material at a rate of ~0.023 emu/g per C/Ga molar ratio, and the ferromagnetism of Mn/C-codoped GaN can be stronger than that of Mn-doped GaN by a factor of ~40. A plausible growth mechanism was proposed, and the role of carbon codoping in tuning the morphology and ferromagnetic property was discussed. Our work suggests that carbon doping in the GaN matrix favors the N sites over the Ga sites, Mn/C-codoping in the GaN matrix is energetically favorable, and the C-codoping strongly enhances the preference of the FM coupling to the AFM coupling between the two doped Mn sites. These suggestions were probed on the basis of first-principles density functional theory electronic structure calculations for a number of model doped structures constructed with a 32-atom 2 × 2 × 2 supercell. (Read more)
- 2. Mater. Sci. Eng. B 126, 222-225 (2006) , “Magnetic properties of a new spintronic material—GaN:Fe”, H. Przybylińska, A. Wolos, M. Kiecana, M. Sawicki, T. Dietl, H. Malissa, C. Simbrunner, M. Wegscheider, H. Sitter, K. Rumpf, P. Granitzer, H. Krenn and W. JantschWe report on metal-organic chemical vapour deposition growth of GaN:Fe and its characterization by means of high-resolution X-ray diffraction, secondary ion mass spectroscopy, electron spin resonance, and magnetization measurements. Electron spin resonance studies demonstrate the existence of Fe in... (Read more)
- 3. J. Phys. Chem. Solids 65, 639-645 (2004) , “Carbothermally-assisted aerosol synthesis of semiconducting materials in the system GaN/Mn”, Jerzy F. Janik , Mariusz Dryga , Cezary Czosnek , Maria Kamiska , Maria Palczewska and Robert T. PaineAerosol-assisted vapor phase synthesis aimed at preparation of magnetic semiconductor nanopowders of Ga1−xMnxN is carried out both from aqueous and methanol solution mixtures of gallium nitrate and manganese (II) nitrate. After an additional pyrolysis at 1000 °C under an ammonia flow,... (Read more)
- 4. J. Appl. Phys. 93, 9697-9702 (2003) , “Growth and characterization of GaN:Mn epitaxial films”, T. Graf, M. Gjukic, M. Hermann, M. S. Brandt, M. Stutzmann, L. Görgens, J. B. Philipp, O. AmbacherThe oxidation states of Mn in epitaxial GaN films grown by plasma induced molecular beam epitaxy were investigated by electron spin resonance (ESR), elastic recoil detection, superconducting quantum interference device magnetization, and photothermal deflection spectroscopy measurements. Comparison... (Read more)
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