PRESSURE-INDUCED AMORPHIZATION AND PHASE-TRANSITIONS IN NALA(MOO4)(2)- A HIGH-PRESSURE X-RAY-DIFFRACTION STUDY

An in situ high pressure X-ray diffraction study of alkali-rare earth dimolybdate NaLa(MoO4)(2) (NLMO) has been carried out in the diamond a nvil cell up to 32.6 GPa at room temperature, using the synchrotron ra diation source. The results have revealed a pressure-induced amorphiza tion near 26 GPa, and two pressure-induced crystal to crystal phase tr ansitions at about similar to 10 GPa and 20 GPa, respectively. The fir st transition is from orthorhombic pseudo-scheelite to the tetragonal scheelite-type structure. For the second transformation a change from scheelite-type structure to a monoclinic structure is proposed. These results are in agreement with the findings of a recent high pressure R aman study on NLMO.