Quasi-hydrostatic powder x-ray diffraction study of the low- and high-pressure phases of CaWO4 up to 28 GPa

Autores UPV
Año
CONGRESO Quasi-hydrostatic powder x-ray diffraction study of the low- and high-pressure phases of CaWO4 up to 28 GPa

Abstract

We have studied CaWO4 under compression at RT by means of synchrotron XRD at the16-IDB beamline of the HPCAT at the Advanced Photon Source. When compressed using Ne as pressure-transmitting medium, we found that CaWO4 transforms from its lowpressure tetragonal structure (scheelite) into a much denser monoclinic structure. Compared with previous measurements [1-4] we found a non-lineal behavior of the unitcell parameters suggesting that deviatory stresses strongly influence the HP structural behavior of CaWO4. To illustrate this fact in Fig. 1 we show results obtained for the scheelite phase in experiments where different pressure media were used. Our quasihydrostatic results (circles) follow a different behavior than previous studies carried out without pressure-transmitting medium or using liquid pressure media