Document Type
Article
Original Publication Date
2006
Journal/Book/Conference Title
Journal of Applied Physics
Volume
100
Issue
12
DOI of Original Publication
10.1063/1.2400805
Date of Submission
November 2015
Abstract
TiO2nanoparticlesdoped with 1%, 5%, and 10% M (M=Co, Fe, and Ni) were prepared by microwave irradiation and characterized using x-ray diffraction, transmission electron microscopy, and magnetometry. The as-prepared samples are found to be paramagnetic at room temperature, with the magnetic susceptibility following the Curie-Weiss law in the investigated range of 2–300K. However, transformation from paramagnetism to room-temperature ferromagnetism (RTFM) was observed by hydrogenating the samples at 400°C. Reheating in air converted the samples back to paramagnetic while rehydrogenating the samples again induced ferromagnetism. It is argued that the reversible RTFM observed is due to interaction between the dopant metal ions and oxygen vacancies produced during hydrogenation. X-ray diffraction of the hydrogenated Co- and Fe-doped samples shows only a single TiO2 phase suggesting that the observed RTFM may be intrinsic, but for the Ni-doped samples the magnetism may arise from metallic Ni on the surfaces of the TiO2nanoparticles.
Rights
Glaspell, G., Panda, A. B., & El-Shall, M. S. Reversible paramagnetism to ferromagnetism in transition metal-doped TiO2 nanocrystals prepared by microwave irradiation. Journal of Applied Physics, 100, 124307 (2006). Copyright © 2006 American Institute of Physics.
Is Part Of
VCU Chemistry Publications
Comments
Originally published at http://dx.doi.org/10.1063/1.2400805