Evidence for a temperature-driven structural transformation in liquid bismuth

¹  Department of Materials Engineering, Ben Gurion University of the Negev - Beer-Sheva 84105, Israel
²  Department of Physics, NRCN - P.O. Box 9001, Beer-Sheva 84190, Israel
³  XSD and IPNS Divisions, Argonne National Laboratory - Argonne, IL, 60439, USA
⁴  Laboratoire Léon Brillouin (CEA-CNRS), CEA/Saclay - 91191 Gif-sur-Yvette cedex, France, EU

Corresponding author: yargreen@zahav.net.il

Received: 2 March 2009
Accepted: 8 April 2009

Abstract

The thermodynamic properties of liquid bismuth have been explored from the melting point to 1100 °C by high-resolution measurements of the density, the heat capacity and the static structure factor. These physical properties display a number of anomalies. In particular, we have observed evidence for the presence of a temperature-driven liquid-liquid structural transformation that takes place at ambient pressure. The latter is characterized by a density discontinuity that occurs at 740 °C. Differential thermal analysis measurements revealed the endothermal nature of this transformation. A rearrangement of liquid bismuth structure was found by neutron diffraction measurements, supporting the existence of a liquid-liquid transformation far above the liquidus.