Novel experimental design for high pressure - high temperature electrical resistance measurements in a 'Paris-Edinburgh' large volume press

TL;DR

This paper introduces a new experimental setup for high-pressure, high-temperature electrical resistance measurements in a large volume press, enabling precise phase transition detection and phase diagram reconstruction of materials like Pb, Sn, and Bi.

Contribution

The novel design allows direct electrical resistance measurement on small samples, increasing sensitivity and simplifying the process for high-pressure, high-temperature phase diagram studies.

Findings

Successfully measured resistance of Pb, Sn, Bi across wide phase space

Reconstructed phase diagrams with high accuracy matching previous data

Established calibration method for temperature and pressure without direct measurements

Abstract

We present a novel experimental design for high sensitivity measurements of the electrical resistance of samples at high pressures (0-6GPa) and high temperatures (300-1000K) in a 'Paris-Edinburgh' type large volume press. Uniquely, the electrical measurements are carried out directly on a small sample, thus greatly increasing the sensitivity of the measurement. The sensitivity to even minor changes in electrical resistance can be used to clearly identify phase transitions in material samples. Electrical resistance measurements are relatively simple and rapid to execute and the efficacy of the present experimental design is demonstrated by measuring the electrical resistance of Pb, Sn and Bi across a wide domain of temperature-pressure phase space and employing it to identify the loci of phase transitions. Based on these results, the phase diagrams of these elements are reconstructed to high accuracy and found to be in excellent agreement with previous studies. In particular, by mapping the locations of several well-studied reference points in the phase diagram of Sn and Bi, it is demonstrated that a standard calibration exists for the temperature and pressure, thus eliminating the need for direct or indirect temperature and pressure measurements. The present technique will allow simple and accurate mapping of phase diagrams under extreme conditions and may be of particular importance in advancing studies of liquid state anomalies.