Paloma Vilanova-Martínez has joined our group. Paloma graduated in Chemistry from the Autonomous University of Madrid. She is working on the study of the micro- and nanostructural flexibility of mixed oxides with interest in catalysis (Project FlexOCat).
Project FlexOCat (2012–2014):
Flexibilidad micro- y nano-estructural en óxidos mixtos de interés catalítico / Micro- and nano-structural flexibility in mixed oxides with catalytic properties.
Spanish Government (MAT2011-27192).
TEM images, quantitative particle size distribution analysis, and SAED patterns indexed as NiFe2O4 spinel of the a mechanosynthesized powder and b after a thermal treatment at 800C
Piezoelectric oxides are currently being considered in combination with magnetic materials for the development of magnetoelectric composites, in which stress transfer across the interface is a key issue. In this context, we report here a detailed study of the mechanochemical activation processes of the ferroelectric perovskite BiScO3–PbTiO3 and of the ferrimagnetic spinel NiFe2O4. Highly sinterable, single-phase nanopowders of both ferroic oxides are synthesised, and used for the reparation of highdensity materials and two-phase composites by hot pressing. Emphasis is put on studying chemical reactions at and interdiffusion across the interface between the two phases using high spatial resolution techniques such as micro X-ray diffraction and piezoresponse force microscopy. The feasibility of preparing magnetoelectric composites by this approach is demonstrated, for which the necessity of controlling physicochemical processes at the interface is key to obtain functionality.
HRTEM image of a crystal of oxidized ∼SbVO4 orientated along the [1 1 0] rutile direction. The white dots correspond to basic rutile cation positions and the superimposed dark bands to sinusoidal waves of cation vacancies. The magenta and blue lines indicate the line scans whose intensity is displayed at the right of the figure. Magenta line runs across the cationic positions while the blue line runs mainly across the cation vacancy waves. A. R. Landa-Cánovas, F. J. García-García y S. Hansen. “Structural Flexibility in ~SbVO4″ Catalysis Today 158, 156–161 (2010).
E. Punzón Quijorna, V. Torres Costa, F. Agulló-Rueda, P. Herrero Fernández, A. Climent, F. Rossi and M. Manso Silván, “TiNxOy/TiN dielectric contrasts obtained by ion implantation of O2+; structural, optical and electrical properties,” J. Phys. D: Appl. Phys. 44(23), 235501 (2011).
Jorge Hernández-Moro has recently joined our group. Jorge graduated in Physics from the University of Salamanca and realized the master on Energies and Fuels for the Future from the Autonomous University of Madrid. He is working on the nanocharacterization of advanced functional coatings (Project FUNCOAT CONSOLIDER INGENIO-2010).
M. Elices, G. Guinea, G. Plaza, C. Karatzas, C. Riekel, F. Agulló-Rueda, R. Daza, and J. Pérez-Rigueiro, “Bioinspired fibers follow the track of natural spider silk,” Macromolecules 44(5), 1166-1176 (2011).
M. Gabás, P. Díaz-Carrasco, F. Agulló-Rueda, P. Herrero, A. R. Landa-Cánovas, and J. R. Ramos-Barrado, “High quality ZnO and Ga:ZnO thin films grown onto crystalline Si (100) by RF magnetron sputtering,” Sol. Energy Mater. Sol. Cells, 95, 2327–2334 (2011) .
