Heat-capacity measurements under uniaxial pressure using a piezo-driven device

TL;DR

This paper introduces a novel piezoelectric-driven method for precise heat capacity measurements under large uniaxial pressure, effective from 8 K to millikelvin, demonstrated on Sr$_2$RuO$_4$.

Contribution

The authors develop and optimize a high-resolution, AC heat-capacity measurement technique under uniaxial pressure suitable for low-temperature physics research.

Findings

Successfully measured heat capacity of Sr$_2$RuO$_4$ under uniaxial pressure.

Achieved high resolution and homogenous strain in the sample.

Adaptable setup for different temperature regimes.

Abstract

We report the development of a technique to measure heat capacity at large uniaxial pressure using a piezoelectric-driven device generating compressive and tensile strain in the sample. Our setup is optimized for temperatures ranging from 8 K down to millikelvin. Using an AC heat-capacity technique we are able to achieve an extremely high resolution and to probe a homogeneously strained part of the sample. We demonstrate the capabilities of our setup on the unconventional superconductor Sr$_2$RuO$_4$. By replacing thermometer and adjusting the remaining setup accordingly the temperature regime of the experiment can be adapted to other temperature ranges of interest.