Electrical Resistance of Liquid Carbon (up to 9000 K) and Liquid Gadolinium (up to 6000 K) at Elevated Pressure and High Temperatures

Abstract

Experiments are carried out on rapid heating by an electric current pulse of plates for anisotropic graphite and gadolinium foil clamped in the same way: between two thick-walled plates of TF-5 glass (heavy flint). In both cases, the glass cells were previously compressed with a clamp to create some initial pressure. During the passage of the current pulse (5 μs), the pressure in the samples is estimated; it increases due to thermal expansion when confined by the glass plates. The electrical resistance of liquid carbon at low pressures (up to 1 kbar) increases with increasing temperature, just as for most conductors. Under limited expansion (increasing pressure), the electrical resistance of liquid carbon becomes constant, independent of the increase in temperature and pressure (up to 9000 K). Unlike carbon, the electrical resistance of liquid gadolinium at elevated pressure (about 1 kbar) practically did not change (~260 µm cm) and remained approximately constant, as at lower pressures (~0.3 kbar); and at high temperatures, up to 6000 K.