Determination of the high-pressure crystal structure of BaWO{sub 4} and PbWO{sub 4}

Journal Article · Thu Jun 01 00:00:00 EDT 2006 · Physical Review. B, Condensed Matter and Materials Physics

DOI:https://doi.org/10.1103/PHYSREVB.73.224103· OSTI ID:20853242

Errandonea, D; Pellicer-Porres, J; Segura, A; Ferrer-Roca, Ch ^[1]; Manjon, F J ^[2]; Kumar, R S; Tschauner, O ^[3]; Lopez-Solano, J; Rodriguez-Hernandez, P; Radescu, S; Mujica, A; Munoz, A ^[4]; Aquilanti, G ^[5]

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1. Departamento Fisica Aplicada-ICMUV, Universitat de Valencia, Edificio de Investigacion, C/Dr. Moliner 50, 46100 Burjassot (Valencia) (Spain)
2. Departamento Fisica Aplicada, Universitat Politecnica de Valencia, Camino de Vera s/n, 46022 Valencia (Spain)
3. High Pressure Science and Engineering Center, Department of Physics, University of Nevada, 4505 Maryland Parkway, Las Vegas, Nevada 89154-4002 (United States)
4. Departamento Fisica Fundamental II, Universidad de La Laguna, La Laguna, Tenerife (Spain)
5. European Synchrotron Radiation Facility, BP 220, Grenoble, F-38043 (France)

We report the results of both angle-dispersive x-ray diffraction and x-ray absorption near-edge structure studies in BaWO{sub 4} and PbWO{sub 4} at pressures of up to 56 GPa and 24 GPa, respectively. BaWO{sub 4} is found to undergo a pressure-driven phase transition at 7.1 GPa from the tetragonal scheelite structure (which is stable under normal conditions) to the monoclinic fergusonite structure whereas the same transition takes place in PbWO{sub 4} at 9 GPa. We observe a second transition to another monoclinic structure which we identify as that of the isostructural phases BaWO{sub 4}-II and PbWO{sub 4}-III (space group P2{sub 1}/n). We have also performed ab initio total-energy calculations which support the stability of this structure at high pressures in both compounds. The theoretical calculations further find that upon increase of pressure the scheelite phases become locally unstable and transform displacively into the fergusonite structure. The fergusonite structure is, however, metastable and can only occur if the transition to the P2{sub 1}/n phases were kinetically inhibited. Our experiments in BaWO{sub 4} indicate that it becomes amorphous beyond 47 GPa.

• OSTI ID: 20853242
• Journal Information: Physical Review. B, Condensed Matter and Materials Physics, Vol. 73, Issue 22; Other Information: DOI: 10.1103/PhysRevB.73.224103; (c) 2006 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 1098-0121
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ABSORPTION SPECTROSCOPY
BARIUM COMPOUNDS
FINE STRUCTURE
LEAD TUNGSTATES
MONOCLINIC LATTICES
PHASE STABILITY
PHASE TRANSFORMATIONS
PRESSURE DEPENDENCE
PRESSURE RANGE GIGA PA
SOLIDS
TETRAGONAL LATTICES
X-RAY DIFFRACTION
X-RAY SPECTROSCOPY