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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Tailoring the physical and chemical properties of Sn1-xCoxO2 nanoparticles: an experimental and theoretical approach

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Author(s):
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Aragon, F. F. H. [1, 2] ; Villegas-Lelovsky, L. [3, 4] ; Cabral, L. [4] ; Lima, M. P. [4] ; Aquino, J. C. R. [1, 2] ; Mathpal, M. C. [1] ; Coaquira, J. A. H. [1] ; da Silva, S. W. [1] ; Nagamine, L. C. C. M. [5] ; Parreiras, S. O. [6] ; Gastelois, P. L. [6] ; Marques, G. E. [5] ; Macedo, W. A. A. [6]
Total Authors: 13
Affiliation:
[1] Univ Brasilia, Inst Fis, Nucleo Fis Aplicada, BR-70910900 Brasilia, DF - Brazil
[2] Univ Nacl San Agustin Arequipa, Lab Peliculas Delgadas, Escuela Profes Fis, Av Independencia S-N, Arequipa - Peru
[3] Univ Estadual Paulista, Dept Fis, IGCE, BR-13506900 Rio Claro, SP - Brazil
[4] Univ Fed Sao Carlos, Ctr Ciencias Exatas & Tecnol, Dept Fis, BR-13565905 Sao Carlos, SP - Brazil
[5] Univ Sao Paulo, Inst Fis, BR-05508090 Sao Paulo - Brazil
[6] CDTN, BR-3127901 Belo Horizonte, MG - Brazil
Total Affiliations: 6
Document type: Journal article
Source: Physical Chemistry Chemical Physics; v. 22, n. 6, p. 3702-3714, FEB 14 2020.
Web of Science Citations: 6
Abstract

In this work, we present a coupled experimental and theoretical first-principles investigation on one of the more promising oxide-diluted magnetic semiconductors, the Sn1-xCoxO2 nanoparticle system, in order to see the effect of cobalt doping on the physical and chemical properties. Our findings suggest that progressive surface enrichment with dopant ions plays an essential role in the monotonous quenching of the surface disorder modes. That weakening is associated with the passivation of the oxygen vacancies as the Co excess at the surface becomes larger. Room-temperature Sn-119 Mossbauer spectroscopy data analysis revealed the occurrence of a distribution of isomer shifts, related to the different non-equivalent surroundings of Sn4+ ions and the coexistence of Sn2+/Sn4+ at the particle surfaces provoked by the inhomogeneous distribution of Co ions, in agreement with the X-ray photoelectron spectroscopy measurements. Magnetic measurements revealed a paramagnetic behavior of the Co ions dispersed in the rutile-type matrix with antiferromagnetic correlations, which become stronger as the Co content is increased. Theoretical calculations show that a defect with two Co mediated by a nearby oxygen vacancy is the most likely defect. The predicted effects of this defect complex are in accordance with the experimental results. (AU)

FAPESP's process: 16/21371-5 - Structural, magnetic and hyperfine properties of nanoparticles of ferrites (MxFe3-xO4, M=Co, Ni, Cu or Zn) and In-Sn-O (ITO) doped with transition metals and rare-earth elements: Potential applications in hyperthermia and gas sensors
Grantee:Luiz Carlos Camargo Miranda Nagamine
Support Opportunities: Regular Research Grants
FAPESP's process: 14/19142-2 - Characterization and processing of semiconductor nanostructures and application as devices
Grantee:Gilmar Eugenio Marques
Support Opportunities: Research Projects - Thematic Grants
FAPESP's process: 17/02317-2 - Interfaces in materials: electronic, magnetic, structural and transport properties
Grantee:Adalberto Fazzio
Support Opportunities: Research Projects - Thematic Grants