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Title: Paramagnetic behavior of Co doped TiO{sub 2} nanocrystals controlled by self-purification mechanism

Abstract

Doping in nanocrystals is a challenging process because of the self- purification mechanism which tends to segregate out the dopants resulting in a greater dopant concentration near the surface than at the interior of nanocrystals. In the present work nanocrystals of TiO{sub 2} doped with different atom % of Co were synthesized by peroxide gel method. XRD analysis confirmed the tetragonal anatase structure and HRTEM images showed the rod-like morphology of the samples. Raman modes of anatase phase of TiO{sub 2} along with weak intensity peaks of Co{sub 3}O{sub 4} for higher Co dopant concentrations were observed for the samples. EPR measurements revealed the presence of cobalt in +2 oxidation state in the TiO{sub 2} matrix. SQUID measurements indicated paramagnetic behavior of the Co doped TiO{sub 2} nanocrystals. The paramagnetic behavior is attributed to an increased concentration of Co{sup 2+} ions and an increased presence of Co{sub 3}O{sub 4} phase near the surface of the TiO{sub 2} nanocrystals due to self-purification mechanism. - Graphical abstract: Variation of the intensity ratios of XRD peaks as a function of atomic ratio of Co. Inset: variation of structure factor for (101) reflection as a function of atomic ratio of Co. Display Omitted -more » Highlights: • Co doped TiO{sub 2} nanocrystals were synthesized by peroxide gel method. • HRTEM images showed Co doped TiO{sub 2} nanocrystals to be rod-like. • EPR spectra showed +2 oxidation states for Co in the samples. • Co doped TiO{sub 2} nanocrystals showed paramagnetic behavior.« less

Authors:
 [1];  [1];  [2]
  1. Centre for Nanoscience and Nanotechnology, University of Kerala, Kariavattom, Thiruvananthapuram 695 581 (India)
  2. UGC-DAE Consortium for Scientific Research (CSR), Khandwa Road, Indore 452 001 (India)
Publication Date:
OSTI Identifier:
22584165
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Solid State Chemistry; Journal Volume: 239; Other Information: Copyright (c) 2016 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; COBALT IONS; COBALT OXIDES; DOPED MATERIALS; ELECTRON SPIN RESONANCE; IMAGES; MAGNETIC PROPERTIES; NANOSTRUCTURES; OXIDATION; PARAMAGNETISM; PEROXIDES; SPECTRA; STRUCTURE FACTORS; SURFACES; TITANIUM OXIDES; TRANSMISSION ELECTRON MICROSCOPY; X-RAY DIFFRACTION

Citation Formats

Anitha, B., Khadar, M. Abdul, E-mail: mabdulkhadar@rediffmail.com, and Banerjee, Alok. Paramagnetic behavior of Co doped TiO{sub 2} nanocrystals controlled by self-purification mechanism. United States: N. p., 2016. Web. doi:10.1016/J.JSSC.2016.04.035.
Anitha, B., Khadar, M. Abdul, E-mail: mabdulkhadar@rediffmail.com, & Banerjee, Alok. Paramagnetic behavior of Co doped TiO{sub 2} nanocrystals controlled by self-purification mechanism. United States. doi:10.1016/J.JSSC.2016.04.035.
Anitha, B., Khadar, M. Abdul, E-mail: mabdulkhadar@rediffmail.com, and Banerjee, Alok. 2016. "Paramagnetic behavior of Co doped TiO{sub 2} nanocrystals controlled by self-purification mechanism". United States. doi:10.1016/J.JSSC.2016.04.035.
@article{osti_22584165,
title = {Paramagnetic behavior of Co doped TiO{sub 2} nanocrystals controlled by self-purification mechanism},
author = {Anitha, B. and Khadar, M. Abdul, E-mail: mabdulkhadar@rediffmail.com and Banerjee, Alok},
abstractNote = {Doping in nanocrystals is a challenging process because of the self- purification mechanism which tends to segregate out the dopants resulting in a greater dopant concentration near the surface than at the interior of nanocrystals. In the present work nanocrystals of TiO{sub 2} doped with different atom % of Co were synthesized by peroxide gel method. XRD analysis confirmed the tetragonal anatase structure and HRTEM images showed the rod-like morphology of the samples. Raman modes of anatase phase of TiO{sub 2} along with weak intensity peaks of Co{sub 3}O{sub 4} for higher Co dopant concentrations were observed for the samples. EPR measurements revealed the presence of cobalt in +2 oxidation state in the TiO{sub 2} matrix. SQUID measurements indicated paramagnetic behavior of the Co doped TiO{sub 2} nanocrystals. The paramagnetic behavior is attributed to an increased concentration of Co{sup 2+} ions and an increased presence of Co{sub 3}O{sub 4} phase near the surface of the TiO{sub 2} nanocrystals due to self-purification mechanism. - Graphical abstract: Variation of the intensity ratios of XRD peaks as a function of atomic ratio of Co. Inset: variation of structure factor for (101) reflection as a function of atomic ratio of Co. Display Omitted - Highlights: • Co doped TiO{sub 2} nanocrystals were synthesized by peroxide gel method. • HRTEM images showed Co doped TiO{sub 2} nanocrystals to be rod-like. • EPR spectra showed +2 oxidation states for Co in the samples. • Co doped TiO{sub 2} nanocrystals showed paramagnetic behavior.},
doi = {10.1016/J.JSSC.2016.04.035},
journal = {Journal of Solid State Chemistry},
number = ,
volume = 239,
place = {United States},
year = 2016,
month = 7
}
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  • Abstract not provided.