J. Mater. Sci. Technol. ›› 2015, Vol. 31 ›› Issue (5): 453-457.DOI: 10.1016/j.jmst.2014.08.013

• Orginal Article • Previous Articles     Next Articles

Synthesis and Room Temperature d0 Ferromagnetic Properties of α-MoO3 Nanofibers

Sandeep K.S. Patel1, Khemchand Dewangan2, *, N.S. Gajbhiye1, *   

  1. 1 Department of Chemistry, Indian Institute of Technology, Kanpur 208016, India; 2 Department of Chemistry, Indira Gandhi National Tribal University, Amarkantak 484886, India
  • Received:2014-06-17 Online:2015-05-20 Published:2015-07-23
  • Contact: Corresponding authors. Tel.: +91 512 259 7423; Fax: +91 512 259 7080. E-mail addresses: dewangankc@gmail.com (K. Dewangan), nsg@iitk.ac.in (N.S. Gajbhiye).
  • Supported by:
    The authors thank the Council of Scientific and Industrial Research (CSIR), New Delhi (India) for the Senior Research Fellowship and DST unit on Nanosciences, IIT Kanpur for the FESEM and Raman measurements.

Abstract: Herein, we report the magnetic properties of α-MoO3 nanofibers synthesized via a hydrothermal method. X-ray photoelectron and Raman spectroscopic studies have been employed to evidence the presence of oxygen vacancy defects in the α-MoO3 nanofibers. To elucidate the oxygen vacancy related ferromagnetism, post-thermal annealing in oxygen and vacuum was performed. The UV emission band of α-MoO3 nanofibers reveals a red shift from oxygen annealed to vacuum annealed, indicating a band-edge reduction. The saturation magnetization of oxygen annealed nanofibers decreases while that of vacuum annealed nanofibers increases. These results strongly confirm that the oxygen vacancies play a significant role in inducing ferromagnetism. The origin of ferromagnetism may be due to the exchange interactions among localized electron spin moments resulting from oxygen vacancies of α-MoO3 nanofibers. The presence of such defects was further supported by the photoluminescence measurements.

Key words: Ferromagnetism, Molybdenum oxide, Annealing treatment, Defects