Zobrazeno 1 - 10
of 73
pro vyhledávání: '"Valmir Antonio Chitta"'
Autor:
Valmir Antonio Chitta
Publikováno v:
Biblioteca Digital de Teses e Dissertações da USPUniversidade de São PauloUSP.
Utilizou-se um Hamiltoniano KP (6x6) do tipo Kane para, se estudar a estrutura de bandas e níveis de Landau para heteroestruturas de semicondutores zincblende dos grupos III-V e II-VI. Os efeitos do acoplamento entre as bandas de condução e valên
Autor:
Valmir Antonio Chitta, Waldomiro Paschoal, C.M. Rocha Remédios, Xavier Pierre Marie Gratens, Lorena Nascimento, A.J. Freitas Cabral
Publikováno v:
Repositório Institucional da USP (Biblioteca Digital da Produção Intelectual)
Universidade de São Paulo (USP)
instacron:USP
Universidade de São Paulo (USP)
instacron:USP
In this work, we show the sorbitol-assisted synthesis method to produce polycrystalline Ni/NiO systems with different phase proportions. The samples were prepared from heat treatment of an aqueous solution of nickel chloride and sorbitol by using a s
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::010eaf6fb23c7e0397c51f25408f6a80
Autor:
H. B. de Carvalho, V. M. Almeida Lage, Alexandre Mesquita, R.T. da Silva, Xavier Pierre Marie Gratens, Valmir Antonio Chitta, M. P. F. de Godoy
Publikováno v:
Repositório Institucional da USP (Biblioteca Digital da Produção Intelectual)
Universidade de São Paulo (USP)
instacron:USP
Scopus
Repositório Institucional da UNESP
Universidade Estadual Paulista (UNESP)
instacron:UNESP
Universidade de São Paulo (USP)
instacron:USP
Scopus
Repositório Institucional da UNESP
Universidade Estadual Paulista (UNESP)
instacron:UNESP
Made available in DSpace on 2021-06-25T10:50:04Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-05-15 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Poly
Autor:
F. H. Aragón, Ismael Gonzales, Xavier Gratens, Valmir Antonio Chitta, Paulo C. Morais, Jose A. H. Coaquira, Waldemar A. A. Macedo, J. C. R. Aquino
Publikováno v:
The Journal of Physical Chemistry C. 121:21670-21677
The present study reports the successful synthesis of Sn1–xCrxO2 nanoparticles with doping content (x) ranging from 0 to 0.20. Samples were synthesized by a polymer precursor method using SnCl2·H2O and Cr(NO3)3·5H2O as metal ion suppliers. In all
Publikováno v:
Repositório Institucional da USP (Biblioteca Digital da Produção Intelectual)
Universidade de São Paulo (USP)
instacron:USP
Universidade de São Paulo (USP)
instacron:USP
Polycrystalline NiMn2O4 samples were synthesized by sol-gel method at 500 °C (S500), 700 °C (S700), and 800 °C (S800). The three samples were then structurally characterized by X-ray diffraction and Rietveld refinement. Results indicate that sampl
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::d0a086237e9ee84da4b963ff250fd934
Autor:
Valmir Antonio Chitta, Xavier Gratens, Gunther Springholz, André Bohomoletz Henriques, P. A. Usachev
Publikováno v:
Physical review letters. 120(21)
We demonstrate that light resonant with the band gap forces the antiferromagnetic semiconductor EuSe to enter ferromagnetic alignment in the picosecond timescale. A photon generates an electron-hole pair, whose electron forms a supergiant spin polaro
Autor:
Xavier Gratens, Hugo Bonette de Carvalho, Gul Rahman, Antonio C. Doriguetto, Valmir Antonio Chitta, Víctor M. García-Suárez, Juliana M. Morbec, Angela O. de Zevallos, Maria Inês Basso Bernardi, Rafael Tomaz da Silva, Alexandre Mesquita, T. Chiaramonte
Publikováno v:
Repositório Institucional da USP (Biblioteca Digital da Produção Intelectual)
Universidade de São Paulo (USP)
instacron:USP
Universidade de São Paulo (USP)
instacron:USP
In this report we present a systematic structural and magnetic analysis of Co-doped ZnO nanoparticles prepared via a microwave-assisted hydrothermal route. The structural data confirm the incorporation of Co ions into the wurtzite ZnO lattice and a C
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::20374f76c9bac3a324e1ef5a64657c57
Autor:
M. M. de Lima, M. A. Boselli, R.T. da Silva, Xavier Gratens, F. P. Rhodes, Antonio C. Doriguetto, A. O. de Zevallos, Marcello Rubens Barsi Andreeta, Andrés Cantarero, Antônio Claret Soares Sabioni, W. B. Ferraz, Valmir Antonio Chitta, Alexandre Mesquita, H. B. de Carvalho, I.S. da Silva, P. P. Neves
Publikováno v:
Scopus
Repositório Institucional da UNESP
Universidade Estadual Paulista (UNESP)
instacron:UNESP
Repositório Institucional da UNESP
Universidade Estadual Paulista (UNESP)
instacron:UNESP
Made available in DSpace on 2022-04-29T07:25:55Z (GMT). No. of bitstreams: 0 Previous issue date: 2015-07-25 Financiadora de Estudos e Projetos Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Coordenação de Aperfeiçoamento d
Effects of Ultrasonic Agitation on the Structural and Magnetic Properties of CoFe 2 O 4 Nanocrystals
Autor:
José Fernando Condeles, Noelio O. Dantas, R.S. Silva, Xavier Gratens, Valmir Antonio Chitta, Sinésio Domingues Franco, Anielle Christine Almeida Silva
Publikováno v:
European Journal of Inorganic Chemistry. 2014:5603-5608
Cobalt ferrite nanocrystals (CoFe2O4) were synthesized by means of ultrasonic agitation and afterward subjected to different annealing temperatures. The structural and morphological properties of the nanocrystals were investigated by means of X-ray d
Autor:
Xavier Gratens, S. C. P. van Kooten, Valmir Antonio Chitta, P. A. Usachev, Gunther Springholz, André Bohomoletz Henriques, A. R. Naupa
Publikováno v:
Journal of Applied Physics. 126:095701
We present a simple semiclassical model to sustain that in europium chalcogenides (EuX), Faraday rotation (FR) in the transparency gap is proportional to the magnetization of the sample, irrespective of the material’s magnetic phase, temperature, o