Tailoring the physical and chemical properties of Sn1−xCoxO2 nanoparticles: an experimental and theoretical approach
| Autor: | L Villegas-Lelovsky, Mohan Chandra Mathpal, S. O. Parreiras, Waldemar A. A. Macedo, S.W. da Silva, J. C. R. Aquino, L. Cabral, Matheus P. Lima, J.A.H. Coaquira, G E Marques, F. H. Aragón, Luiz Carlos Camargo Miranda Nagamine, P L Gastelois |
|---|---|
| Přispěvatelé: | Universidade de Brasília (UnB), Univ Nacl San Agustin Arequipa, Universidade Estadual Paulista (Unesp), Universidade Federal de São Carlos (UFSCar), Universidade de São Paulo (USP), CDTN |
| Rok vydání: | 2020 |
| Předmět: |
Quenching
Materials science Dopant Passivation General Physics and Astronomy 02 engineering and technology Magnetic semiconductor 010402 general chemistry 021001 nanoscience & nanotechnology 01 natural sciences 0104 chemical sciences Ion Condensed Matter::Materials Science Paramagnetism X-ray photoelectron spectroscopy OXIGÊNIO Chemical physics Antiferromagnetism Physical and Theoretical Chemistry 0210 nano-technology |
| Zdroj: | Repositório Institucional da USP (Biblioteca Digital da Produção Intelectual) Universidade de São Paulo (USP) instacron:USP Web of Science Repositório Institucional da UNESP Universidade Estadual Paulista (UNESP) instacron:UNESP |
| Popis: | Made available in DSpace on 2020-12-10T19:52:01Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-02-14 Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Brazilian Agency Fundacao de Amparo a Pesquisa do Distrito Federal (FAP/DF) 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. Univ Brasilia, Inst Fis, Nucleo Fis Aplicada, BR-70910900 Brasilia, DF, Brazil Univ Nacl San Agustin Arequipa, Lab Peliculas Delgadas, Escuela Profes Fis, Av Independencia S-N, Arequipa, Peru Univ Estadual Paulista, Dept Fis, IGCE, BR-13506900 Rio Claro, SP, Brazil Univ Fed Sao Carlos, Ctr Ciencias Exatas & Tecnol, Dept Fis, BR-13565905 Sao Carlos, SP, Brazil Univ Sao Paulo, Inst Fis, BR-05508090 Sao Paulo, Brazil CDTN, BR-3127901 Belo Horizonte, MG, Brazil Univ Estadual Paulista, Dept Fis, IGCE, BR-13506900 Rio Claro, SP, Brazil CNPq: 305.647/2015-6 FAPESP: 2016/21371-5 FAPESP: 2014/19142-2 FAPESP: 2017/02317-2 Brazilian Agency Fundacao de Amparo a Pesquisa do Distrito Federal (FAP/DF): 0193.001.345/2016 Brazilian Agency Fundacao de Amparo a Pesquisa do Distrito Federal (FAP/DF): 0193001.196/2016 |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|