A uniaxial stress capacitive dilatometer for high-resolution thermal expansion and magnetostriction under multiextreme conditions

TL;DR

This paper introduces a miniaturized capacitive dilatometer capable of high-resolution thermal expansion and magnetostriction measurements under extreme conditions such as very low temperatures, high magnetic fields, and high uniaxial stress.

Contribution

The authors present a novel uniaxial stress capacitive dilatometer designed for high-resolution measurements under multi-extreme conditions, including low temperatures, high magnetic fields, and high pressure.

Findings

Achieves length change resolution of 0.02 Å at low temperatures

Operates effectively down to 20 mK in high magnetic fields

Exerts uniaxial stress up to 3 kbar on samples

Abstract

Thermal expansion and magnetostriction are directional dependent thermodynamic quantities. For the characterization of novel quantum phases of matter it is required to study materials under multi-extreme conditions, in particular down to very low temperatures, in very high magnetic fields, as well as under high pressure. We developed a miniaturized capacitive dilatometer suitable for temperatures down to 20 mK and usage in high magnetic fields, which exerts a large spring force between 40 to 75 N on the sample. This corresponds to a uniaxial stress up to 3 kbar for a sample with cross-section of (0.5~mm)$^2$. We describe the design and performance test of the dilatometer which resolves length changes with high resolution of $0.02 \mathrm{\AA}$ at low temperatures. The miniaturized device can be utilized in any standard cryostat, including dilution refrigerators or the commercial physical property measurement system.