Advanced search
Start date
Betweenand

Structural characterization of nanopowders of semiconductor ferroelectric oxides

Grant number: 07/03510-9
Support type:Regular Research Grants
Duration: July 01, 2008 - June 30, 2011
Field of knowledge:Engineering - Materials and Metallurgical Engineering
Principal Investigator:Silvania Lanfredi Nobre
Grantee:Silvania Lanfredi Nobre
Home Institution: Faculdade de Ciências e Tecnologia (FCT). Universidade Estadual Paulista (UNESP). Campus de Presidente Prudente. Presidente Prudente , SP, Brazil

Abstract

This research project approaches the structural characterization of nanopowders of ferroelectric oxides accompanied of structural refinement from X-ray diffraction date based on the Rietveld method. Furthermore, the consolidation and enhancement of a set of research lines of the Laboratory of Composites and Functional Ceramics (LaCCeF) should be reached. In this sense, four research lines implemented in the LaCCeF, involving the preparation and characterization of nanometric and nanostructured particles will be directly benefited. In addition, a new research line termed of Nanoscale Effect, in which both the electric and dielectric properties of nanoparticle and nanostructured one are investigated will also undergo a positive impact. Materials of interest belong to the kind of lead free ferroelectric termed of Tetragonal Tungsten Bronze (TTB) family, which exhibits potential application in technologic areas as linear dielectric and ferroelectric. In this project, TTB host structures Sr2NaNb5O15 and K2NdNb5O15, as well as its solid solutions with transition metal will be prepared using three chemical synthesis methods, as follow: Modified Poliol method, Combustion method, Polymeric Precursors method (Pechini). Classical oxide preparation route based on the conventional mechanical mixture of oxides/carbonates, using high efficiency milling process, an operational processing technique of Laboratory of Composites and Functional Ceramics (LaCCeF - FAPESP), DFQB/FCT/ UNESP will be also used. Both host structures Sr2NaNb5O15 and K2NdNb5O15 will compose with KSr2Nb5O15 and Sr3SnNb4O15, actually under investigation in the LaCCeF, a wide base of crystalline structures with distincts forms of occupation of specific sites. The process of optimization of parameters time and calcination temperatures, which are necessaries to the preparation of nanoparticle and nanostructured one of Sr2NaNb5O15, K2NdNb5O15 and its single phase solid solutions will be monitored by infrared spectroscopy, surface area (BET) measurement, thermal analysis (DSC e TGA) and luminescence spectroscopy. The Rietveld method, FULLPROF program, will be used to attain the profile of adjusting of the set of diffraction lines and refinement of the structural parameters, as atomic positions. From crystallographic parameters, the tridimensional representation of unitary cellule of above mentioned compounds will be constructed, using the CaRIne Crystallography 3.1®, CaRIne Crystallography 3.1®sr e CaRIne Crystallography 4.0® software. These softwares and the Jade 8 Plus software package will be used to the indexation of the diffraction pattern. All 4 softwares were acquired by research funding supported by CNPq - Process 47.4627/2004-7. (AU)

Scientific publications (7)
(References retrieved automatically from Web of Science and SciELO through information on FAPESP grants and their corresponding numbers as mentioned in the publications by the authors)
MATOS, JUAN; LANFREDI, SILVANIA; MONTANA, RICMARY; NOBRE, MARCOS A. L.; FERNANDEZ, MARIA C.; ANIA, CONCHI O. Photochemical reactivity of apical oxygen in KSr2Nb5O15 materials for environmental remediation under UV irradiation. Journal of Colloid and Interface Science, v. 496, p. 211-221, JUN 15 2017. Web of Science Citations: 3.
LANFREDI, SILVANA; SILVEIRA, GISETE S.; POTENSA, BRUNO S.; NOBRE, MARCOS A. L. ZnO/Zn/Amorphous Carbon Matrix Nanostructured Composite Powder: a New Photocatalyst for Dye. MRS ADVANCES, v. 1, n. 19, p. 1327-1332, 2016. Web of Science Citations: 0.
LANFREDI, SILVANIA; NOBRE, MARCOS A. L.; MORAES, PAULA G. P.; MATOS, JUAN. Photodegradation of phenol red on a Ni-doped niobate/carbon composite. CERAMICS INTERNATIONAL, v. 40, n. 7, A, p. 9525-9534, AUG 2014. Web of Science Citations: 11.
LANFREDI, S.; DARIE, C.; BELLUCCI, F. S.; COLIN, C. V.; NOBRE, M. A. L. Phase transitions and interface phenomena in the cryogenic temperature domain of a niobate nanostructured ceramic. DALTON TRANSACTIONS, v. 43, n. 28, p. 10983-10998, 2014. Web of Science Citations: 16.
LANFREDI, SILVANIA; PALACIO, GUSTAVO; BELLUCCI, FELIPE S.; COLIN, CLAIRE V.; NOBRE, MARCOS A. L. Thermistor behaviour and electric conduction analysis of Ni-doped niobate ferroelectric: the role of multiple beta parameters. JOURNAL OF PHYSICS D-APPLIED PHYSICS, v. 45, n. 43 OCT 31 2012. Web of Science Citations: 13.
LANFREDI, S.; BRITO, I. A. O.; POLINI, C.; NOBRE, M. A. L. Deriving the magnitude of niobium off-center displacement in ferroelectric niobates from infrared spectroscopy. Journal of Applied Spectroscopy, v. 79, n. 2, p. 254-260, MAY 2012. Web of Science Citations: 3.
LANFREDI, SILVANIA; NOBRE, MARCOS A. L.; LIMA, ALAN R. F. Análise cristalográfica da solução sólida com estrutura tipo Tungstênio Bronze de niobato de potássio e estrôncio dopado com ferro. Química Nova, v. 33, n. 5, p. 1071-1076, 2010.

Please report errors in scientific publications list by writing to: cdi@fapesp.br.
Filed patent(s) as a result of this research project

PROCESSO DE OBTENÇÃO DE CATALISADORES HETEROGÊNEOS E PRODUTO OBTIDO BR1020150017650 - Universidade Estadual Paulista (UNESP) . Fernando Storti; Marcos Augusto de Lima Nobre; Silvania Lanfredi Nobre - January 2015, 27