Ceramics based bismuth vanadate are conductors of oxygen ions and they are used as solid electrolytes in pressure sensors and fuel cells. The g-phase of Bi4V2O11 can be stabilized at T0 by partial substitution of V5+ ion by Cu2+ and Zn2+ ions to provide high electrical conductivity values between 100 and 400oC. Polycrystalline samples of Bi4V1.8Cu0.1Zn0.1O10.7 were obtained after 4h sintering at 800 °C. Investigations were made about densification process and electrical conductivity related to the effect of addition of Zr0.88Y0.12O1.94.
Na última semana, entre os dias 30 de março e 02 de abril, ocorreu no Instituto de Física de São Carlos, Universidade de São Paulo, a 1a Escola Brasileira de Espectroscopia de Absorção de raios-x (EBARX), organizada pelo coordenador do Grupo de Pesquisa Crescimento de Cristais e Materiais Cerâmicos, Prof. Valmor Roberto Mastelaro. O evento contou com apoio do Centro para o Desenvolvimento de Materiais Funcionais (CDMF), da CAPES e do Instituto de Física de São Carlos (IFSC) e recebeu 67 pesquisadores de Instituições de todo Brasil os quais participaram de aulas teóricas e práticas de análise durante a EBARX.
The effect of microwave annealing on the electrical characteristics of lanthanum doped bismuth titanate films obtained by the polymeric precursor method
Lanthanum doped bismuth titanate thin films (Bi3.25La0.75Ti3O12 – BLT) were produced by the polymeric precursor method and crystallized in a domestic microwave oven and in conventional furnace. Using platinum coated silicon substrates configuration, ferroelectric properties of the films were determined with remanent polarization Pr and a coercive field Ec of 3.9 mC/cm2 and 70 kV/cm for the film annealed in the microwave oven and 20 mC/cm2 and 52 kV/cm for the film annealed in conventional furnace, respectively. The films annealed in conventional furnace exhibited excellent retention-free characteristics at low infant periods indicating that BLT thin films can be a promise material for use in nonvolatile memories. On the other hand, the pinning of domains wall causes a strong decay at low infant periods for the films annealed in the microwave furnace which makes undesireable the application for future FeRAMS memories.
Alexandre Zirpole Simoes, Miguel Angel Ramirez Gil, B.D. Stojanovic, Elson Longo, Jose Arana Varela
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