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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. Phys. Rev. B 74, 235208 (2006) , “Theoretical study of the magnetism of Mn-doped ZnO with and without defects”, D. Iuan, B. Sanyal, and O. ErikssonWe calculate the exchange interaction parameters of a classical Heisenberg Hamiltonian for Mn-doped ZnO (Mn concentration between 5% and 20%) by an ab initio Korringa-Kohn-Rostoker coherent-potential-approximation method in the framework of density functional theory. A weak antiferromagnetic... (Read more)
- 3. Phys. Rev. B 74, 155203 (2006) , “Antisite effect on hole-mediated ferromagnetism in (Ga,Mn)As”, R. C. Myers, B. L. Sheu, A. W. Jackson, A. C. Gossard, P. Schiffer, N. Samarth, and D. D. AwschalomWe study the Curie temperature and hole density of (Ga,Mn)As while systematically varying the As-antisite density. Hole compensation by As-antisites limits the Curie temperature and can completely quench long-range ferromagnetic order in the low doping regime of 1%2% Mn. Samples are grown by... (Read more)
- 4. Phys. Rev. B 75, 035322 (2007) , “Ab initio study of electronic and magnetic properties of the C-codoped Ga1−xMnxN (100) surface”, Q. Wang, Q. Sun, and P. JenaFirst principles calculations based on gradient corrected density functional theory have been carried out to study the magnetic coupling between Mn atoms in pure and carbon doped Ga1−xMnxN thin films. We show that the ground state of Mn-doped GaN (100) thin... (Read more)
- 5. Phys. Rev. B 75, 085203 (2007) , “Structural and magnetic properties of Mn-implanted Si”, Shengqiang Zhou, K. Potzger, Gufei Zhang, A. Mücklich, F. Eichhorn, N. Schell, R. Grötzschel, B. Schmidt, W. Skorupa, M. Helm, J. Fassbender, and D. GeigerStructural and magnetic properties in Mn-implanted, p-type Si were investigated. High resolution structural analysis techniques such as synchrotron x-ray diffraction revealed the formation of MnSi1.7 nanoparticles already in the as-implanted samples. Depending on the Mn fluence,... (Read more)
- 6. Phys. Rev. B 74, 115203 (2006) , “From ferromagnetic to antiferromagnetic interactions in n-type Zn1–xMnxO: An electron paramagnetic resonance study”, A. Ben Mahmoud, H. J. von Bardeleben, J. L. Cantin, A. Mauger, E. Chikoidze, and Y. DumontContradictory results concerning the formation of a ferromagnetic state in Mn doped ZnO layers have been reported in the last years. We present the results of an electron paramagnetic resonance study on homogeneous single phase n-type conductive Zn1xMnxO... (Read more)
- 7. J. Appl. Phys. 100, 033717 (2006) , “Magnetic and carrier transport properties of Mn-doped p-type semiconductor LaCuOSe: An investigation of the origin of ferromagnetism”, Hiroshi Yanagi, Shuichi Ohno, Toshio Kamiya, Hidenori Hiramatsu, Masahiro Hirano, and Hideo HosonoLaCuOSe is a wide band gap p-type semiconductor in which high density positive holes can be doped to exhibit degenerate conduction. These features should allow room-temperature ferromagnetism in a dilute magnetic semiconductor (DMS), which follows a theoretical prediction [T. Dietl et al.,... (Read more)
- 8. J. Magn. Magn. Mater. 302, 118 (2005) , “Magnetism origin of Mn-doped ZnO nanoclusters”, J.H. Li, D.Z. Shen, J.Y. Zhang, D.X. Zhao, B.S. Li, Y.M. Lu, Y.C. Liu , X.W. FanZnMnO nanoclusters were synthesized by the sol–gel method. The structural and magnetic characters were investigated. The XRD spectrum shows ZnMnO nanoclusters are hexagonal wurtzite structures and a small quantity of ZnMn2O4 phase is also present in the spectrum. The percentages of Zn and Mn... (Read more)
- 9. Phys. Rev. B 68, 125204 (2003) , “Magnetic properties of substitutional 3d transition metal impurities in silicon carbide”, M. S. Miao and Walter R. L. LambrechtUsing the linearized muffin-tin orbital (LMTO) method within both the atomic sphere approximation and full potential (FP) implementations and within the local spin-density-functional method and a supercell approach, we study the magnetic properties of cubic (3C) silicon carbide (SiC) doped by... (Read more)
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