Measurement of the Absolute Value of Specific Heat by Using AC-Calorimeter under High Pressure up to 10 GPa and Low Temperature down to 0.3 K

Abstract

We developed the AC-calorimeter for measuring the absolute value of specific heat up to 10 GPa. We used Bridgman anvil cell made of WC with the top of 3 mm in diameter. A hollow at the top prevents expansion of the sample space over the anvil top. As for the thermometer and the heater, two chip resistors were mounted on the fringe of the Cu-Be gasket in the shape of a frying pan. Thereby, the thermometer is free from pressure. In order to thermally isolate the gasket from the anvil, diamond powder of 0.25 μm was laid on the anvil top. Two jumps of specific heat at the superconducting transitions of Pb (3.3 mg) and In (5.0 mg) are observed under pressures up to 9 GPa as clearly as at ambient pressure.