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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 75, 113201 (2007) , “Local structure around Mn atoms in Si crystals implanted with Mn+ studied using x-ray absorption spectroscopy techniques”, A. Wolska, K. Lawniczak-Jablonska, M. Klepka, M. S. Walczak, and A. MisiukThe local order around Mn atoms in the Mn-implanted Si samples, with ferromagnetic properties, has been investigated by use of x-ray-absorption spectroscopy techniques. Analysis of both extended x-ray-absorption fine structure and x-ray absorption near-edge structure spectra clearly indicates that... (Read more)
- 3. 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)
- 4. Phys. Rev. B 74, 245205 (2006) , “Mn incorporation in as-grown and annealed (Ga,Mn)As layers studied by x-ray diffraction and standing-wave fluorescence”, V. Holý, Z. Matj, O. Pacherová, V. Novák, M. Cukr, K. Olejník, and T. JungwirthA combination of high-resolution x-ray diffraction and a technique of x-ray standing-wave fluorescence at grazing incidence is employed to study the structure of a (Ga,Mn)As-diluted magnetic semiconductor and its changes during post-growth annealing steps. We find that the film is formed by a... (Read more)
- 5. Phys. Rev. B 74, 235213 (2006) , “Mn 3d electronic configurations in (Ga1−xMnx)As ferromagnetic semiconductors and their influence on magnetic ordering”, F. Kronast, R. Ovsyannikov, A. Vollmer, H. A. Dürr, W. Eberhardt, P. Imperia, D. Schmitz, G. M. Schott, C. Ruester, C. Gould, G. Schmidt, K. Brunner, M. Sawicki, and L. W. MolenkampWe applied x-ray absorption spectroscopy and x-ray magnetic circular dichroism (XMCD) at the Mn 2p-3d resonances to study the Mn 3d electronic configuration and the coupling of Mn 3d magnetic moments in various Ga1−xMnxAs films.... (Read more)
- 6. Thin Solid Films 496, 169-173 (2006) , “Green luminescence from Mn ions in ZnO–GeO2 glasses prepared by sol–gel method and their glass ceramics”, Tomoe Sanada, Kazuhiro Yamamoto, Noriyuki Wada , Kazuo KojimaZn2SiO4:Mn2+ is one of the green light luminants used for cathode ray tubes of televisions. Recently, optical materials emitting strong visible light under lower energy excitation have been expected. To obtain new luminants of high quality, we prepared Mn ion doped ZnO–GeO2 glasses and glass... (Read more)
- 7. Chem. Phys. Lett. 415, 337 (2005) , “No ferromagnetism in Mn doped ZnO semiconductors”, J. Alaria, P. Turek, M. Bernard, M. Bouloudenine, A. Berbadj, N. Brihi, G. Schmerber, S. Colis , A. DiniaPolycrystalline Zn1 − xMnxO was synthesized by co-precipitation method with xvarying between 0.01 and 0.10. Although X-ray diffraction patterns show a typical würtzite structure with no additional peaks for all samples, Raman spectroscopy indicates the appearance of an additional mode in... (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. Superlatt. Microstruct. 38, 413-420 (2005) , “EPR study on magnetic Zn1−xMnxO”, Mariana Diaconu, Heidemarie Schmidt, Andreas Pöppl, Rolf Böttcher, Joachim Hoentsch, Andreas Rahm, Holger Hochmuth, Michael Lorenz ,Marius GrundmannDiluted magnetic semiconductors (DMS), systems formed by replacing cations of the host semiconductor material with transition-metal ions, are developed for further use in spintronics. A good combination as a DMS is Zn1−xMnxO due to the ZnO wide band gap (3.37 eV) and the matching ionic... (Read more)
- 10. 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)
- 11. Mater. Sci. Eng. A 375-377, 620-624 (2004) , “Evolution of the microstructure of disperse ZnO powders obtained by the freeze-drying method”, Z. V. Marinkovic, O. Milosevic, M. V. Nikolic, M. G. Kakazey, M. V. Karpec, T. V. Tomila , M. M. RisticFreeze-drying, as a cryochemical powder processing method is applied in the synthesis of ZnO submicrometer to nanosized powders. The process involves rapid freezing of the sprayed precursor solution, drying under vacuum by sublimation of the solvent and salt decomposition to oxide by thermal... (Read more)
- 12. 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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