COSYMETCOX · Confined synthesis of metastable complex oxides
FP7 — People (Marie Curie Actions)
- Duration
- 2011-09-01 → 2015-02-28
- EU contribution
- €87,500
- Participants
- 1
- Scheme
- MC-CIG
Lines connect the coordinator with its partners.
Results in brief
Confined synthesis of metastable complex oxides
The COSYMETCOX project aimed at studying the stabilization of metastable functional oxides by confinement and finding strategies to integrate these phases in devices. In particular the project focused in three especially relevant systems: mangetoelectric ε-Fe2O3; λ-Ti3O5, showing a room-temperature photoreversible phase transition and monoclinic La0.7Sr0.3MnO3, presenting an increased Curie temperature. The project has been successful in developing a robust method to prepare ε-Fe2O3 films on technologically relevant substrates as SrTiO3, making possible to discover that this metastable polymorph of Fe2O3 is ferroelectric at room temperature. Since ε-Fe2O3 was already known to be ferrimagnetic at ambient conditions, it is thus the first multiferroic single metal oxide to be reported. The confined synthesis of the monoclinic La0.7Sr0.3MnO3 was attempted in silica matrices using the metal nitrates dissolved in ethanol in co-synthesis with the preparation of the silica using tetraethylortosilicate. It was very surprising not to obtain, after thermally treating the gels, the expected manganite but large amounts of α-quartz. It was discovered that Sr2+ played a key role in the devitrification of the xerogel in α-quartz and exploited in the unprecedented growth of the piezoelectric α-quartz on silicon. The study of the mechanisms of crystallization of epitaxial quartz on Si(100) was subsequently integrated in the project. Regarding the study of λ-Ti3O5, the obtained results were not new and somehow disappointing and the task was abandoned. Finally, the project allowed exploring the crystallization of new metastable phases under negative pressures in liquids. Although this task faced several experimental hurdles, it is now an ongoing line in the research activity portafolio of the fellow.
Data: CORDIS, © European Union
Project objective
Nowadays, a pressing demand for new materials with appealing multifunctional properties is pulling the research in materials science. In this context, as the properties of inorganic solids are intimately linked to their crystal structures, an interesting approach to extend the range of properties and applications of a particular compound is discovering and stabilising at ambient conditions new metastable polymorphs of thermodynamically stable structures. A fruitful strategy to stabilize metastable phases is the synthesis of nanoscale polymorphs under matrix confinement. Interestingly, some of those metastable polymorphs which can only be stabilized in spatially restricted fields, display outstanding multifunctional properties that could find important technological applications. Exploring, identifying and understanding the fundamental aspects of this stabilizing mechanism will be the first objective of the project.Some model metastable polymorphs with applicability in Information and Communication Technologies as memory or sensor devices that will be investigated in the project are: ε-Fe2O3, λ-Ti3O5 and a new phase of La0.7Sr0.3MnO3.The matrix confined synthesis is not always well matched for the integration of these nano-oxides into devices which requires a thorough control of the microstructure of the functional oxides and its precise positioning in a technological substrate. Addressing the above limitation is the second leading objective of the project.""
Original text from CORDIS.
Participants
- AGENCIA ESTATAL CONSEJO SUPERIOR DE INVESTIGACIONES CIENTIFICAS · MadridCoordinatorSpain
Links
Data: CORDIS, © European Union