Structural and optical studies of FeSb2 under high pressure

Nanostructured orthorhombic FeSb2 was formed along with an amorphous phase, by mechanical alloying from a mixture of Fe and Sb powders. The influence of pressure on the structural and optical properties of the material was investigated by X-ray diffraction (XRD) and Raman spectroscopy (RS) up to 28.2 and 45.2 GPa, respectively. The volume fraction of the amorphous phase increased with increasing pressure. For pressures above 14.3 GPa, a tetragonal FeSb2 phase was also observed. For the orthorhombic FeSb2 phase, the pressure dependence of the volume fitted to a Birch-Murnaghan equation of state gave a bulk modulus B-0=75.5 +/- 3.2 GPa, and its derivative B'(0)=7.2 +/- 0.7. For the orthorhombic FeSb2 phase, the Raman active A(g)(2) mode was observed up to 28.3 GPa, while the B-1g(2) mode was not for pressures larger than 14 GPa. For pressures above 21 GPa, the Raman active A(1g) mode of a tetragonal FeSb2 phase was observed. (C) 2012 Elsevier B.V. All rights reserved.