Apparatus Design for Measuring of the Strain Dependence of the Seebeck Coefficient of Single Crystals

TL;DR

This paper introduces a novel apparatus capable of measuring the Seebeck coefficient of single crystals under tunable uniaxial strain at cryogenic temperatures, enabling detailed study of strain-dependent thermoelectric properties.

Contribution

The paper presents a new apparatus design that allows in-situ strain tuning during Seebeck coefficient measurements at cryogenic temperatures, demonstrated on BaFe2As2 crystals.

Findings

Seebeck coefficient anisotropy measured under uniaxial stress.

Apparatus achieves up to 0.7% anisotropic strain.

Results agree with previous clamp-based measurements.

Abstract

We present the design and construction of an apparatus that measures the Seebeck coefficient of single crystals under in-situ tunable strain at cryogenic temperatures. A home-built three piezostack apparatus applies uni-axial stress to a single crystalline sample and modulates anisotropic strain up to 0.7%. An alternating heater system and cernox sensor thermometry measures the Seebeck coefficient along the uniaxial stress direction. To demonstrate the efficacy of this apparatus, we applied uniaxial stress to detwin single crystals of BaFe2As2 in the orthorhombic phase. The obtained Seebeck coefficient anisotropy is in good agreement with previous measurements using a mechanical clamp.