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

Autor(es):Mostrar menos -

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]

Afiliação do(s) autor(es)

^[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

• Tipo de documento: Artigo Científico
• Fonte: Physical Chemistry Chemical Physics; v. 22, n. 6, p. 3702-3714, FEB 14 2020.
• Citações Web of Science: 6

Resumo

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)

• Processo FAPESP: 16/21371-5 - Propriedades estruturais, magnéticas e hiperfinas de nanopartículas de ferritas (MxFe3-xO4, M=Co, Ni, Cu ou Zn) e de In-Sn-O (ITO) dopadas com metais de transição e terras-raras: Potenciais aplicações em hipertermia e em sensores de gás
• Beneficiário: Luiz Carlos Camargo Miranda Nagamine
• Modalidade de apoio: Auxílio à Pesquisa - Regular
• Processo FAPESP: 14/19142-2 - Caracterização e processamento de nanoestruturas semicondutoras e aplicações como dispositivos
• Beneficiário: Gilmar Eugenio Marques
• Modalidade de apoio: Auxílio à Pesquisa - Temático
• Processo FAPESP: 17/02317-2 - Interfaces em materiais: propriedades eletrônicas, magnéticas, estruturais e de transporte
• Beneficiário: Adalberto Fazzio
• Modalidade de apoio: Auxílio à Pesquisa - Temático