Crystallographic structural variations in nano-crystalline Sc₂O₃ under pressure

Abstract

The present manuscript reports high pressure investigations on nano-crystalline Scandium Oxide (Sc2O3) through synchrotron angle dispersive x-ray diffraction technique (ADXRD) up to a pressure of ~35.4 GPa using a diamond-anvil cell (DAC). The sample, having a cubic or bixbyite structure at ambient conditions, underwent substantial changes in crystallographic parameters while exhibiting phase stability i.e. does not undergo any structural phase transition upto the studied pressure. The lattice parameters and the unit cell volume decrease significantly with an increase in pressure revealing compressible nature of the crystal structure. The pressure-volume data is fitted using third-order Birch-Murnaghan equation of state to calculate bulk modulus and its first derivative, which yields zero pressure bulk modulus of 213.5 GPa, with B' = 10.3 and the corresponding ambient volume per unit molecule comes out to be 59.17 Ǻ3.