Two-stage amorphization of scandium molybdate at high pressure

Using Raman spectroscopy and X-ray diffraction we find that at high pressure amorphization of scandium molybdate occurs in two stages. Excessive broadening of molybdate internal modes arising from distortion and disordering of MoO4 tetrahedra, together with rapid weakening of diffraction from large d-spacings and disappearance of diffraction from small d-spacings suggest gross molybdate ion disorder above 4 GPa. On the other hand, complete amorphization occurs at the significantly higher pressure of 12 GPa, where diffraction disappears completely. The amorphization is also found to be irreversible.