The equation of state of the Pmmn phase of NiSi

Oliver T Lord; Andrew R Thomson; Elizabeth T H Wann; Ian G Wood; David P Dobson; Lidunka Vocadlo

doi:10.1107/S1600576715020087

The equation of state of the Pmmn phase of NiSi

J Appl Crystallogr. 2015 Nov 28;48(Pt 6):1914-1920. doi: 10.1107/S1600576715020087. eCollection 2015 Dec 1.

Authors

Oliver T Lord¹, Andrew R Thomson², Elizabeth T H Wann³, Ian G Wood³, David P Dobson³, Lidunka Vocadlo³

Affiliations

¹ School of Earth Sciences, University of Bristol , Wills Memorial Building, Queen's Road, Bristol BS81RJ, UK.
² School of Earth Sciences, University of Bristol , Wills Memorial Building, Queen's Road, Bristol BS81RJ, UK ; Department of Earth Sciences, University College London , Gower Street, London WC1E 6BT, UK.
³ Department of Earth Sciences, University College London , Gower Street, London WC1E 6BT, UK.

Abstract

The equation of state of the orthorhombic phase of NiSi with Pmmn symmetry has been determined at room temperature from synchrotron-based X-ray diffraction measurements of its lattice parameters, made in a diamond anvil cell. Measurements were performed up to 44 GPa, using Ne as the pressure medium and Au as the pressure standard. The resulting pressure-volume (P-V) data have been fitted with a Birch-Murnaghan equation of state of third order to yield V₀ = 11.650 (7) Å³ atom^-1, K₀ = 162 (3) GPa and K₀' = 4.6 (2). In addition, P-V data have been collected on Ni₅₃Si₄₇ in the B20 structure using both Ne and He as the pressure media and Cu and Au as the pressure standards, also to 44 GPa. A fit using the same Birch-Murnaghan equation of state of third order yields V₀ = 11.364 (6) Å³ atom^-1, K₀ = 171 (4) GPa and K₀' = 5.5 (3).

Keywords: NiSi; diamond anvil cells; equations of state; high pressure.