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Title: Room-temperature ferromagnetism in Co and Nb co-doped TiO{sub 2} nanoparticles

Co- and Nb-doped TiO{sub 2} nanoparticles encapsulated with amorphous SiO{sub 2} were synthesized by our novel preparation method. An anatase TiO{sub 2} single-phase structure was confirmed using X-ray diffraction. The particle size could be controlled to be about 5 nm. The composition of these nanoparticles was investigated by X-ray fluorescence analysis. X-ray absorption near-edge structure spectra showed that the Ti{sup 4+} and Co{sup 2+} states were dominant in our prepared samples. A reduction in the coordination number was also confirmed. The dependence of the electrical conductivity on the frequency was measured by an LCR meter, and the carrier concentration was determined. The magnetization curves for the nanoparticles indicated ferromagnetic behavior at room temperature. We concluded that the ferromagnetism originated in oxygen vacancies around the transition metal ions.
Authors:
; ; ; ; ;  [1]
  1. Department of Physics, Graduate School of Engineering, Yokohama National University, 79-5 Tokiwadai, Hodogaya, Yokohama, Kanagawa 240-8501 (Japan)
Publication Date:
OSTI Identifier:
22391189
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Conference Proceedings; Journal Volume: 1649; Journal Issue: 1; Conference: IRAGO Conference 2014, Tsukuba-city, Ibaraki (Japan), 6-7 Nov 2014; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
77 NANOSCIENCE AND NANOTECHNOLOGY; COBALT COMPOUNDS; COBALT IONS; CONCENTRATION RATIO; DOPED MATERIALS; ELECTRIC CONDUCTIVITY; FERROMAGNETISM; MAGNETIZATION; NANOPARTICLES; NIOBIUM COMPOUNDS; PARTICLE SIZE; SILICON OXIDES; TEMPERATURE RANGE 0273-0400 K; TITANIUM IONS; TITANIUM OXIDES; VACANCIES; X-RAY DIFFRACTION; X-RAY FLUORESCENCE ANALYSIS