Specific Heat of Ca0.33Na0.67Fe2As2

TL;DR

This study measures the specific heat of Ca0.33Na0.67Fe2As2 single crystals, revealing a discontinuity at the superconducting transition temperature that aligns with other hole-doped iron-based superconductors, highlighting its potential as a quality metric.

Contribution

First measurement of the specific heat of Ca0.33Na0.67Fe2As2, providing insights into its superconducting properties and comparison with related compounds.

Findings

Discontinuity in specific heat at Tc is 105 +- 5 mJ/molK2.

deltaC/Tc values are consistent with other hole-doped iron superconductors.

Measured specific heat data supports the use of deltaC/Tc as a quality indicator.

Abstract

The specific heat of single crystal hole-doped Ca0.33Na0.67Fe2As2, Tc(onset)=33.7 K, was measured from 0.4 to 40 K. The discontinuity in the specific heat at Tc, deltaC, divided by Tc is 105 +- 5 mJ/molK2, consistent with values found previously for hole-doped Ba0.6K0.4Fe2As2 and somewhat above the general trend for deltaC/Tc vs Tc for the iron based superconductors established by Bud'ko, Ni and Canfield. The usefulness of measured valued of deltaC/Tc as an important metric for the quality of samples is discussed.