Structural changes in liquid Fe at high pressures and high temperatures from synchrotron X-ray diffraction

High-energy synchrotron X-ray diffraction measurements on liquid iron in th e vicinity of the delta-gamma -liquid triple point (to 2300 K and 5 GPa) re veal significant changes in the structure of the liquid upon increasing pre ssure and temperature. The second and third neighbor shells in the g(r) shi ft to shorter distances and develop new structure with increasing pressure. The results can be interpreted in terms of the liquid acquiring bcc-like l ocal order which evolves to a mixture of bcc- and fcc-like local order as p ressure and/or temperature are raised.