Anisotropic thermal expansion and uniaxial pressure dependence of superconducting and magnetic transitions in ErNi2B2C

TL;DR

This study investigates the anisotropic thermal expansion of ErNi2B2C single crystals, distinguishing phase transitions and estimating how uniaxial pressure influences superconducting and magnetic states, revealing pressure-induced suppression of weak ferromagnetism.

Contribution

First detailed anisotropic thermal expansion measurements on ErNi2B2C, analyzing phase transitions and their pressure dependencies using Ehrenfest relation.

Findings

All three phase transitions are clearly distinguished in thermal expansion data.

Uniaxial pressure dependencies of transitions are estimated, showing suppression of weak ferromagnetism.

Weak ferromagnetic state can be suppressed by small hydrostatic pressures of a few kbar.

Abstract

We present anisotropic thermal expansion measurements on single crystalline ErNi2B2C. All three, superconducting, antiferromagnetic and weak ferromagnetic phase transitions are unambiguously distinguished in the data. Anisotropic uniaxial pressure dependencies of the transitions are estimated based on the Ehrenfest relation, leading to a conclusion, in particular, that weak ferromagnetic state will be suppressed by small, order of several kbar, hydrostatic pressure.