title: Pressure-induced amorphization of YVO₄:Eu³⁺ nanoboxes.
abstract: A structural transformation from the zircon-type structure to an amorphous phase has been found in YVO4:Eu(3+) nanoboxes at high pressures above 12.7 GPa by means of x-ray diffraction measurements. However, the pair distribution function of the high-pressure phase shows that the local structure of the amorphous phase is similar to the scheelite-type YVO4. These results are confirmed both by Raman spectroscopy and Eu(3+) photoluminescence which detect the phase transition to a scheelite-type structure at 10.1 and 9.1 GPa, respectively. The irreversibility of the phase transition is observed with the three techniques after a maximum pressure in the upstroke of around 20 GPa. The existence of two (5)D0-->(7)F0 photoluminescence peaks confirms the existence of two local environments for Eu(3+), at least for the low-pressure phase. One environment is the expected for substituting Y(3+) and the other is likely a disordered environment possibly found at the surface of the nanoboxes.
authors.affiliation: Institut für Geowissenschaften, Goethe-Universität, Altenhöferallee 1, D-60438 Frankfurt am Main, Germany.
authors.forename: J
authors.initials: J
authors.lastname: Ruiz-Fuertes
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authors.lastname: León-Luis
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authors.lastname: Schrodt
authors.forename: F J
authors.initials: FJ
authors.lastname: Manjón
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authors.lastname: Ray
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authors.lastname: Santamaría-Pérez
authors.forename: J A
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authors.forename: H M
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authors.lastname: Ortiz
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authors.lastname: Errandonea
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authors.lastname: Ferrer-Roca
authors.forename: A
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authors.lastname: Segura
authors.forename: D
authors.initials: D
authors.lastname: Martínez-García
authors.forename: V
authors.initials: V
authors.lastname: Lavín
authors.forename: U R
authors.initials: UR
authors.lastname: Rodríguez-Mendoza
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authors.initials: A
authors.lastname: Muñoz