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Journal of Nanotechnology
Volume 2016 (2016), Article ID 8281247, 13 pages
http://dx.doi.org/10.1155/2016/8281247
Research Article

Influence of Fe-Doping on the Structural and Magnetic Properties of ZnO Nanopowders, Produced by the Method of Pulsed Electron Beam Evaporation

1Institute of Electrophysics, Russian Academy of Sciences, Ural Branch, Amundsen Street 106, Yekaterinburg 620016, Russia
2Yeltsin Ural Federal University, Mira Street 19, Yekaterinburg 620002, Russia

Received 24 July 2015; Accepted 10 February 2016

Academic Editor: Oded Millo

Copyright © 2016 V. G. Il’ves et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Linked References

  1. J. M. D. Coey and S. A. Chambers, “Oxide dilute magnetic semiconductors—fact or fiction?” MRS Bulletin, vol. 33, no. 11, pp. 1053–1058, 2008. View at Publisher · View at Google Scholar
  2. T. Dietl, “A ten-year perspective on dilute magnetic semiconductors and oxides,” Nature Materials, vol. 9, no. 12, pp. 965–974, 2010. View at Publisher · View at Google Scholar
  3. H. Ohno, “A window on the future of spintronics,” Nature Materials, vol. 9, no. 12, pp. 952–954, 2010. View at Publisher · View at Google Scholar
  4. R. Singh, “Unexpected magnetism in nanomaterials,” Journal of Magnetism and Magnetic Materials, vol. 346, pp. 58–73, 2013. View at Publisher · View at Google Scholar
  5. R. B. Morgunov and A. I. Dmitriev, “Spin dynamics in magnetic semiconductor nanostructures,” Physics of the Solid State, vol. 51, p. 1985, 2009. View at Publisher · View at Google Scholar
  6. T. Dietl, H. Ohno, F. Matsukura, J. Cibert, and D. Ferrand, “Zener model description of ferromagnetism in zinc-blende magnetic semiconductors,” Science, vol. 287, no. 5455, pp. 1019–1022, 2000. View at Publisher · View at Google Scholar · View at Scopus
  7. K. Sato and H. Katayama-Yoshida, “Electronic structure and ferromagnetism of transition-metal-impurity-doped zinc oxide,” Physica B: Condensed Matter, vol. 308–310, pp. 904–907, 2001. View at Publisher · View at Google Scholar
  8. S. J. Pearton, D. P. Norton, M. P. Ivill et al., “Ferromagnetism in transition-metal doped ZnO,” Journal of Electronic Materials, vol. 36, no. 4, pp. 462–471, 2007. View at Publisher · View at Google Scholar · View at Scopus
  9. C. Liu, F. Yun, and H. Morkoç, “Ferromagnetism of ZnO and GaN: a review,” Journal of Materials Science: Materials in Electronics, vol. 16, article 555, 2005. View at Publisher · View at Google Scholar
  10. F. Pan, C. Song, X. J. Liu, Y. C. Yang, and F. Zeng, “Ferromagnetism and possible application in spintronics of transition-metal-doped ZnO films,” Materials Science and Engineering: R: Reports, vol. 62, no. 1, pp. 1–35, 2008. View at Publisher · View at Google Scholar
  11. B. B. Straumal, A. A. Mazilkin, S. G. Protasova et al., “Magnetization study of nanograined pure and Mn-doped ZnO films: formation of a ferromagnetic grain-boundary foam,” Physical Review B, vol. 79, no. 20, Article ID 205206, 2009. View at Publisher · View at Google Scholar · View at Scopus
  12. T. Tietze, M. Gacic, G. Schütz, G. Jakob, S. Brück, and E. Goering, “XMCD studies on Co and Li doped ZnO magnetic semiconductors,” New Journal of Physics, vol. 10, Article ID 055009, 2008. View at Publisher · View at Google Scholar · View at Scopus
  13. L. I. Burova, N. S. Perov, A. S. Semisalova et al., “Effect of the nanostructure on room temperature ferromagnetism and resistivity of undoped ZnO thin films grown by chemical vapor deposition,” Thin Solid Films, vol. 520, no. 14, pp. 4580–4585, 2012. View at Publisher · View at Google Scholar · View at Scopus
  14. N. H. Hong, J. Sakai, and V. Brizé Hong, “Observation of ferromagnetism at room temperature in ZnO thin films,” Journal of Physics: Condensed Matter, vol. 19, no. 3, Article ID 036219, 2007. View at Publisher · View at Google Scholar
  15. K. Ackland, L. M. A. Monzon, M. Venkatesan, and J. M. D. Coey, “Magnetism of nanostructured CeO2,” IEEE Transactions on Magnetics, vol. 47, no. 10, pp. 3509–3512, 2011. View at Publisher · View at Google Scholar · View at Scopus
  16. Y. L. Zheng, C. M. Zhen, X. Q. Wang, L. Ma, X. L. Li, and D. L. Hou, “Room-temperature ferromagnetism observed in alumina films,” Solid State Sciences, vol. 13, no. 8, pp. 1516–1519, 2011. View at Publisher · View at Google Scholar
  17. C. Z. Wang, Z. Chen, Y. He, L. Y. Li, and D. Zhang, “Structure, morphology and properties of Fe-doped ZnO films prepared by facing-target magnetron sputtering system,” Applied Surface Science, vol. 255, no. 15, pp. 6881–6887, 2009. View at Publisher · View at Google Scholar
  18. J. M. A. Almeida, P. E. C. Santos, L. P. Cardoso, and C. T. Meneses, “A simple method to obtain Fe-doped CeO2 nanocrystals at room temperature,” Journal of Magnetism and Magnetic Materials, vol. 327, pp. 185–188, 2013. View at Publisher · View at Google Scholar
  19. S. Y. Sokovnin, V. G. Il'ves, A. I. Surdo, I. I. Mil'man, and M. I. Vlasov, “Effect of iron doping on the properties of nanopowders and coatings on the basis of Al2O3 produced by pulsed electron beam evaporation,” Nanotechnologies in Russia, vol. 8, no. 7-8, pp. 466–481, 2013. View at Publisher · View at Google Scholar · View at Scopus
  20. V. G. Kytin, V. A. Kulbachinskii, D. S. Glebov, L. I. Burova, A. R. Kaul, and O. V. Reukova, “The conductivity and magnetic properties of zinc oxide thin films doped with cobalt,” Semiconductors, vol. 44, no. 2, pp. 155–160, 2010. View at Publisher · View at Google Scholar
  21. G. Y. Ahn, S.-I. Park, and C. S. Kim, “Enhanced ferromagnetic properties of diluted Fe doped ZnO with hydrogen treatment,” Journal of Magnetism and Magnetic Materials, vol. 303, no. 2, pp. e329–e331, 2006. View at Publisher · View at Google Scholar
  22. W. Zhang, J. Zhao, Z. Liua, and Z. Liu, “Structural, optical and magnetic properties of Zn1-xFexO powders by sol-gel method,” Applied Surface Science, vol. 284, pp. 49–52, 2013. View at Publisher · View at Google Scholar
  23. F. Wang, W.-W. Huang, S.-Y. Li, A.-Q. Lian, X.-T. Zhang, and W. Cao, “The magnetic properties of FexZn1−xO synthesized via the solid-state reaction route: experiment and theory,” Journal of Magnetism and Magnetic Materials, vol. 340, pp. 5–9, 2013. View at Publisher · View at Google Scholar
  24. X. C. Wang, W. B. Mi, and D. F. Kuang, “Microstructure, magnetic and optical properties of sputtered polycrystalline ZnO films with Fe addition,” Applied Surface Science, vol. 256, no. 6, pp. 1930–1935, 2010. View at Publisher · View at Google Scholar · View at Scopus
  25. R. Elilarassi and G. Chandrasekaran, “Synthesis and characterization of ball milled Fe-doped ZnO diluted magnetic semiconductor,” Optoelectronics Letters, vol. 8, no. 2, pp. 109–112, 2012. View at Publisher · View at Google Scholar
  26. Y. Kimishima, M. Ueharaa, K. Iriea et al., “Production of bulk dilute ferromagnetic semiconductor by mechanical milling,” Journal of Magnetism and Magnetic Materials, vol. 320, no. 20, pp. e674–e677, 2008. View at Publisher · View at Google Scholar
  27. A. K. Srivastavaa, M. Deepaa, N. Bahadura, and M. S. Goyat, “Influence of Fe doping on nanostructures and photoluminescence of sol–gel derived ZnO,” Materials Chemistry and Physics, vol. 114, no. 1, pp. 194–198, 2009. View at Publisher · View at Google Scholar
  28. P. Dhiman, J. Chand, A. Kumar, R. K. Kotnala, K. M. Batoo, and M. Singh, “Synthesis and characterization of novel Fe@ZnO nanosystem,” Journal of Alloys and Compounds, vol. 578, pp. 235–241, 2013. View at Publisher · View at Google Scholar · View at Scopus
  29. H. Gu, Y. Jiang, and M. Yan, “Defect-induced room temperature ferromagnetism in Fe and Na co-doped ZnO nanoparticles,” Journal of Alloys and Compounds, vol. 521, pp. 90–94, 2012. View at Publisher · View at Google Scholar
  30. T. Pandiyarajan, R. Udayabhaskar, and B. Karthikeyan, “Microstructure and enhanced exciton-phonon coupling in Fe doped ZnO nanoparticles,” Spectrochimica Acta A: Molecular and Biomolecular Spectroscopy, vol. 103, pp. 173–178, 2013. View at Publisher · View at Google Scholar
  31. S. M. Ramay, M. Saleem, S. Atiq et al., “RKKY magnetic interactions in chemically synthesized Zn0.95−xFe0.05AlxO (x=0, 0.03, 0.05, 0.07) nanocrystallites,” Arabian Journal of Chemistry, 2013. View at Publisher · View at Google Scholar
  32. R. Saleh, N. F. Djaja, and S. P. Prakoso, “The correlation between magnetic and structural properties of nanocrystalline transition metal-doped ZnO particles prepared by the co-precipitation method,” Journal of Alloys and Compounds, vol. 546, pp. 48–56, 2013. View at Publisher · View at Google Scholar
  33. R. Saleh, S. P. Prakoso, and A. Fishli, “The influence of Fe doping on the structural, magnetic and optical properties of nanocrystalline ZnO particles,” Journal of Magnetism and Magnetic Materials, vol. 324, no. 5, pp. 665–670, 2012. View at Publisher · View at Google Scholar · View at Scopus
  34. A. P. Thurber, G. Alanko, G. L. Beausoleil II, K. N. Dodge, C. B. Hanna, and A. Punnoose, “Unusual crystallite growth and modification of ferromagnetism due to aging in pure and doped ZnO nanoparticles,” Journal of Applied Physics, vol. 111, no. 7, Article ID 07C319, 2012. View at Publisher · View at Google Scholar
  35. B. Panigrahy, M. Aslam, and D. Bahadur, “Effect of Fe doping concentration on optical and magnetic properties of ZnO nanorods,” Nanotechnology, vol. 23, no. 11, Article ID 115601, 2012. View at Publisher · View at Google Scholar
  36. R. Hong, H. Wen, C. Liu, J. Chen, and J. Liao, “Dopant concentration dependence of structure, optical, and magnetic properties of ZnO:Fe thin films,” Journal of Crystal Growth, vol. 314, no. 1, pp. 30–33, 2011. View at Publisher · View at Google Scholar
  37. P. Dhiman, S. K. Sharma, M. Knobel, R. Ritu, and M. Singh, “Magnetic properties of Fe doped ZnO nanosystems synthesized by solution combustion method,” Research Journal of Recent Sciences, vol. 1, no. 8, pp. 48–52, 2012. View at Google Scholar
  38. M. V. Limaye, S. B. Singh, R. Das, P. Poddar, and S. K. Kulkarni, “Room temperature ferromagnetism in undoped and Fe doped ZnO nanorods: microwave-assisted synthesis,” Journal of Solid State Chemistry, vol. 184, no. 2, pp. 391–400, 2011. View at Publisher · View at Google Scholar
  39. C. S. Prajapati, A. Kushwaha, and P. P. Sahay, “Influence of Fe doping on the structural, optical and acetone sensing properties of sprayed ZnO thin films,” Materials Research Bulletin, vol. 48, no. 7, pp. 2687–2695, 2013. View at Publisher · View at Google Scholar
  40. S. George, S. Pokhrel, T. Xia et al., “Use of a rapid cytotoxicity screening approach to engineer a safer zinc oxide nanoparticle through iron doping,” ACS Nano, vol. 4, no. 1, pp. 15–29, 2010. View at Publisher · View at Google Scholar · View at Scopus
  41. D. Karmakar, S. K. Mandal, R. M. Kadam et al., “Ferromagnetism in Fe-doped ZnO nanocrystals: experiment and theory,” Physical Review B, vol. 75, no. 14, Article ID 144404, 2007. View at Publisher · View at Google Scholar
  42. A. Franco Jr. and T. E. P. Alvesb, “Room temperature ferromagnetism in combustion reaction prepared iron-doped zinc oxide nanoparticles,” Materials Science in Semiconductor Processing, vol. 16, no. 6, pp. 1804–1807, 2013. View at Publisher · View at Google Scholar
  43. J. Anghel, A. Thurber, D. A. Tenne, C. B. Hanna, and A. Punnoose, “Correlation between saturation magnetization, bandgap, and lattice volume of transition metal (M=Cr, Mn, Fe, Co, or Ni) doped Zn1−xMxO nanoparticles,” Journal of Applied Physics, vol. 107, no. 9, Article ID 09E314, 2010. View at Publisher · View at Google Scholar
  44. C. Xia, C. Hu, Y. Tian, B. Wan, J. Xu, and X. He, “Room-temperature ferromagnetic properties of Ni-doped ZnO rod arrays,” Physica E: Low-dimensional Systems and Nanostructures, vol. 42, no. 8, pp. 2086–2090, 2010. View at Publisher · View at Google Scholar
  45. Z.-R. Wei, Z.-Q. Li, and G.-Y. Dong, “Origin of high-temperature ferromagnetism in Zn0.98Fe0.02O alloys prepared by hydrothermal method,” Journal of Magnetism and Magnetic Materials, vol. 320, no. 6, pp. 916–918, 2008. View at Publisher · View at Google Scholar
  46. H. Liu, J. Yang, Y. Zhang, Y. Wang, and M. Wei, “Ferromagnetism and exchange bias in Fe-doped ZnO nanocrystals,” Materials Chemistry and Physics, vol. 112, no. 3, pp. 1021–1023, 2008. View at Publisher · View at Google Scholar · View at Scopus
  47. X. X. Wei, C. Song, K. W. Geng, F. Zeng, B. He, and F. Pan, “Local Fe structure and ferromagnetism in Fe-doped ZnO films,” Journal of Physics: Condensed Matter, vol. 18, no. 31, p. 7471, 2006. View at Publisher · View at Google Scholar
  48. Y. Lin, D. Jiang, F. Lin, W. Shi, and X. Ma, “Fe-doped ZnO magnetic semiconductor by mechanical alloying,” Journal of Alloys and Compounds, vol. 436, no. 1-2, pp. 30–33, 2007. View at Publisher · View at Google Scholar · View at Scopus
  49. H. Liu, J. Yang, Y. Zhang, L. Yang, M. Wei, and X. Ding, “Structure and magnetic properties of Fe-doped ZnO prepared by the sol-gel method,” Journal of Physics: Condensed Matter, vol. 21, no. 14, Article ID 145803, 2009. View at Publisher · View at Google Scholar
  50. D. Y. Inamdar, A. K. Pathak, I. Dubenko, N. Ali, and S. Mahamuni, “Room temperature ferromagnetism and photoluminescence of Fe Doped ZnO nanocrystals,” The Journal of Physical Chemistry C, vol. 115, no. 48, pp. 23671–23676, 2011. View at Publisher · View at Google Scholar
  51. S. J. Han, J. W. Song, C. H. Yang et al., “A key to room-temperature ferromagnetism in Fe-doped ZnO : Cu,” Applied Physics Letters, vol. 81, no. 22, p. 4212, 2002. View at Publisher · View at Google Scholar
  52. P. K. Sharma, R. K. Dutta, A. C. Pandey, S. Layek, and H. C. Verma, “Effect of iron doping concentration on magnetic properties of ZnO nanoparticles,” Journal of Magnetism and Magnetic Materials, vol. 321, no. 17, pp. 2587–2591, 2009. View at Publisher · View at Google Scholar
  53. M. Bouloudenine, N. Viart, S. Colis, J. Kortus, and A. Dinia, “Antiferromagnetism in bulk Zn1−xCoxO magnetic semiconductors prepared by the coprecipitation technique,” Applied Physics Letters, vol. 87, no. 5, Article ID 052501, 2005. View at Publisher · View at Google Scholar
  54. P. Sati, C. Deparis, C. Morhain, S. Schafer, and A. Stepanov, “Antiferromagnetic interactions in single crystalline Zn1−xCoxO thin films,” Physical Review Letters, vol. 98, Article ID 137204, 2007. View at Publisher · View at Google Scholar
  55. T. Fukumura, Z. Jin, M. Kawasaki et al., “Magnetic properties of Mn-doped ZnO,” Applied Physics Letters, vol. 78, no. 7, pp. 958–960, 2001. View at Publisher · View at Google Scholar
  56. J. H. Park, M. G. Kim, H. M. Jang, S. R. Yu, and Y. M. Kim, “Co-metal clustering as the origin of ferromagnetism in Co-doped ZnO thin films,” Applied Physics Letters, vol. 84, no. 8, pp. 1338–1340, 2004. View at Publisher · View at Google Scholar
  57. C. N. R. Rao and F. L. Deepak, “Absence of ferromagnetism in Mn- and Co-doped ZnO,” Journal of Materials Chemistry, vol. 15, no. 5, pp. 573–578, 2005. View at Publisher · View at Google Scholar
  58. J. M. D. Coey, M. Venkatesan, and C. B. Fitzgerald, “Donor impurity band exchange in dilute ferromagnetic oxides,” Nature Materials, vol. 4, no. 2, pp. 173–179, 2005. View at Publisher · View at Google Scholar
  59. S. Y. Sokovnin and V. G. Il'ves, Using of Pulsed Electron Beam for Producing Nanopowders of some Oxides Metals, RIO UB RAS, Yekaterinburg, Russia, 2012, http://ubras.uran.ru/node/2612, http://ubras.uran.ru/sites/default/files/u66/Sokovnin_Orig_1.jpg.
  60. S. Yu. Sokovnin and V. Il'ves, “Production of nanopowders using pulsed electron beam,” Ferroelectrics, vol. 436, no. 1, pp. 101–107, 2012. View at Publisher · View at Google Scholar
  61. B. Aleman, Y. Ortega, J. A. Garcıa, P. Fernandez, and J. Piqueras, “Fe solubility, growth mechanism, and luminescence of Fe doped ZnO nanowires and nanorods grown by evaporation-deposition,” Journal of Applied Physics, vol. 110, no. 1, Article ID 014317, 2011. View at Publisher · View at Google Scholar
  62. S.-Y. Seo, C.-H. Kwak, S.-H. Kim et al., “Local structural, magnetic, and optical properties of  Zn1-xFexO thin films,” Journal of Crystal Growth, vol. 312, no. 14, pp. 2093–2097, 2010. View at Publisher · View at Google Scholar
  63. P. Wu, G. Saraf, Y. Lu et al., “Ferromagnetism in Fe-implanted a-plane ZnO films,” Applied Physics Letters, vol. 89, no. 1, Article ID 012508, 2006. View at Publisher · View at Google Scholar · View at Scopus
  64. B. B. Straumal, S. G. Protasova, A. A. Mazilkin et al., “Ferromagnetic behaviour of Fe-doped ZnO nanograined films,” Beilstein Journal of Nanotechnology, vol. 4, no. 1, pp. 361–369, 2013. View at Publisher · View at Google Scholar · View at Scopus
  65. S. Banerjee, M. Mandal, N. Gayathri, and M. Sardar, “Enhancement of ferromagnetism upon thermal annealing in pure ZnO,” Applied Physics Letters, vol. 91, no. 18, Article ID 182501, 2007. View at Publisher · View at Google Scholar
  66. A. J. Behan, A. Mokhtari, H. J. Blythe et al., “Two magnetic regimes in doped ZnO corresponding to a dilute magnetic semiconductor and a dilute magnetic insulator,” Physical Review Letters, vol. 100, no. 4, Article ID 047206, 2008. View at Publisher · View at Google Scholar
  67. N. Khare, M. J. Kappers, M. Wei, M. G. Blamire, and J. L. MacManus-Driscoll, “Defect-induced ferromagnetism in Co-doped ZnO,” Advanced Materials, vol. 18, no. 11, pp. 1449–1452, 2006. View at Publisher · View at Google Scholar
  68. C. Song, K. W. Geng, F. Zeng et al., “Giant magnetic moment in an anomalous ferromagnetic insulator: Co-doped ZnO,” Physical Review B, vol. 73, no. 2, Article ID 024405, 2006. View at Publisher · View at Google Scholar
  69. C. Song, F. Zeng, Y. X. Shen et al., “Local Co structure and ferromagnetism in ion-implanted Co-doped LiNbO3,” Physical Review B, vol. 73, no. 17, Article ID 172412, 2006. View at Publisher · View at Google Scholar
  70. C. N. Wu, T. S. Wu, S. Y. Huang et al., “Ferromagnetism in cluster free, transition metal doped high κ dilute magnetic oxides: films and nanocrystals,” Journal of Applied Physics, vol. 113, no. 17, Article ID 17C309, 2013. View at Publisher · View at Google Scholar
  71. C. Song and F. Pan, “Metal-doped magnetic oxides,” in Transition Semiconductors and Semimetals, vol. 88, chapter 7, pp. 227–259, Elsevier, Philadelphia, Pa, USA, 2013. View at Google Scholar
  72. D. Chakraborti, S. Ramachandran, G. Trichy, J. Narayan, and J. T. Prater, “Magnetic, electrical, and microstructural characterization of ZnO thin films codoped with Co and Cu,” Journal of Applied Physics, vol. 101, no. 5, Article ID 053918, 2007. View at Publisher · View at Google Scholar
  73. D. Chakraborti, G. R. Trichy, J. T. Prater, and J. Narayan, “The effect of oxygen annealing on ZnO : Cu and ZnO : (Cu,Al) diluted magnetic semiconductors,” Journal of Physics D: Applied Physics, vol. 40, no. 24, pp. 7606–7613, 2007. View at Publisher · View at Google Scholar
  74. P. K. Sharma, R. K. Dutta, A. C. Pandey, S. Layek, and H. C. Verma, “Effect of iron doping concentration on magnetic properties of ZnO nanoparticles,” Journal of Magnetism and Magnetic Materials, vol. 321, no. 17, pp. 2587–2591, 2009. View at Publisher · View at Google Scholar · View at Scopus
  75. K. Sato, L. Bergqvist, J. Kudrnovský et al., “First-principles theory of dilute magnetic semiconductors,” Reviews of Modern Physics, vol. 82, no. 2, pp. 1633–1690, 2010. View at Publisher · View at Google Scholar · View at Scopus
  76. X. Chen, Z. Zhou, K. Wang et al., “Ferromagnetism in Fe-doped tetra-needle like ZnO whiskers,” Materials Research Bulletin, vol. 44, no. 4, pp. 799–802, 2009. View at Publisher · View at Google Scholar
  77. C. Liu, D. Meng, H. Pang et al., “Influence of Fe-doping on the structural, optical and magnetic properties of ZnO nanoparticles,” Journal of Magnetism and Magnetic Materials, vol. 324, no. 20, pp. 3356–3360, 2012. View at Publisher · View at Google Scholar
  78. Y. Q. Wang, S. L. Yuan, L. Liu et al., “Ferromagnetism in Fe-doped ZnO bulk samples,” Journal of Magnetism and Magnetic Materials, vol. 320, no. 8, pp. 1423–1426, 2008. View at Publisher · View at Google Scholar
  79. X. C. Wang, W. B. Mi, and D. F. Kuang, “Microstructure, magnetic and optical properties of sputtered polycrystalline ZnO films with Fe addition,” Applied Surface Science, vol. 256, no. 6, pp. 1930–1935, 2010. View at Publisher · View at Google Scholar
  80. J. M. Coey, M. Venkatesan, and C. B. Fitzgerald, “Donor impurity band exchange in dilute ferromagnetic oxides,” Nature Materials, vol. 4, no. 2, pp. 173–179, 2005. View at Publisher · View at Google Scholar
  81. S. Y. Sokovnin, V. G. Il'Ves, A. I. Medvedev, and A. M. Murzakaev, “Investigation of properties of ZnO-Zn-Cu nanopowders obtained by pulsed electron evaporation,” Inorganic Materials: Applied Research, vol. 4, no. 5, pp. 410–419, 2013. View at Publisher · View at Google Scholar · View at Scopus
  82. J. M. D. Coey, K. Wongsaprom, J. Alaria, and M. Venkatesan, “Charge-transfer ferromagnetism in oxide nanoparticles,” Journal of Physics D: Applied Physics, vol. 41, no. 13, Article ID 134012, 2008. View at Publisher · View at Google Scholar
  83. J. M. Coey, P. Stamenov, R. D. Gunning, M. Venkatesan, and K. Paul, “Ferromagnetism in defect-ridden oxides and related materials,” New Journal of Physics, vol. 12, no. 5, Article ID 053025, 2010. View at Publisher · View at Google Scholar
  84. L. Y. Li, Y. H. Cheng, X. G. Luo et al., “Room-temperature ferromagnetism and the scaling relation between magnetization and average granule size in nanocrystalline Zn/ZnO core–shell structures prepared by sputtering,” Nanotechnology, vol. 21, no. 14, Article ID 145705, 2010. View at Publisher · View at Google Scholar
  85. X. Zhang, Y. H. Cheng, L. Y. Li et al., “Evidence for high-Tc ferromagnetism in Znx(ZnO)1−x granular films mediated by native point defects,” Physical Review B: Condensed Matter and Materials Physics, vol. 80, no. 17, Article ID 174427, 2009. View at Publisher · View at Google Scholar