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Scientists Analyse the Behaviour of Rare-Earth Orthovanadates under High Pressure

Friday, July 18, 2014

Ana Belén Martínez | | +34 93 592 4050

Rare-earth orthovanadates are technologically important materials with applications as scintillators or photocatalysts materials in lithium ion batteries. In particular they have attracted considerable interest due to potential applications in hydrogen production, offering cleaner energy solutions.

A group of international researchers from India, Spain and Mexico have studied the structure and properties of the rare-earth orthovanadate HoVO4 under high pressure conditions. The team, coordinated by Daniel Errandonea (Universidad de Valencia), was composed by Alka B. Garg (Bhabha Atomic Research Centre), P. Rodríguez-Hernández and A. Muñoz (Universidad de La Laguna), S. López-Moreno (Universidad Autónoma del Estado de Hidalgo) and Catalin Popescu (ALBA Synchrotron).

HoVO4's structure sequence under high pressure conditions.

In this study, researchers combined experimental and theoretical work to determine the structure of the high pressure phases of HoVO4, one of the less studied orthovanadates under high pressure. X-ray diffraction experiments were performed at MSPD beamline (Materials Science Powder Diffraction) of the ALBA Synchrotron and at XRD1 beamline in Elettra.

Results revealed how, under high pressure conditions, this material has the following structure sequence: zircon → scheelite → fergusonite. Calculations fully agreed with the experiments, showing a high consistency, and suggesting the presence of another phase transition at higher pressure (P > 32 GPa).

“By squeezing orthovanadates at pressures hundreds of thousand times greater than atmospheric pressure we tested their structural and mechanical properties. Our findings contribute to improve the knowledge of the physical properties of other materials having the same geometric structural arrangement that orthovanadates", says Daniel Errandonea, leader of the group.

This study contributes to a better understanding of materials under high pressure conditions and its results may have implications in both “technological applications and geophysics”, says Catalin Popescu, one of the researchers and member of the MSPD beamline of the ALBA Synchrotron.

  • X-ray diffraction experiments were performed at ALBA Synchrotron (Spain) and Elettra Synchrotron (Italy).
  • This material may have applications as photocatalyst for hydrogen production, improving renewable energy sources.
  • This work has been highlighted in the Journal of Physics Condensed Matter. It has been also chosen for IOPselect, a special collection of IOP articles chosen from their quality.

“High-pressure structural behaviour of HoVO4: combined XRD experiments and ab initio calculations” Alka B. Garg, D. Errandonea, P. Rodríguez-Hernández, S. López-Moreno, A. Muñoz and Catalin Popescu. Journal of Physics: Condensed Matter 26 265402 (2014).

The ALBA Synchrotron:
ALBA is the Spanish synchrotron light source. It is a complex of electron accelerators to produce synchrotron light, which allows visualization of the atomic structure of matter as well as the study of its properties. ALBA is in operation since May 2012 and has seven experimental beamlines. This scientific infrastructure produces 5.000 hours of beamtime per year and is available for the academic and the industrial sector to give service to more than 1.000 researchers every year.