Specific heat of K071Na0.29Fe2As2 at very low temperatures

Abstract

A commercially available calorimeter has been used to investigate the specific heat of a high-quality \kn\ single crystal. The addenda heat capacity of the calorimeter is determined in the temperature range $0.02\mathrm{K}\le T\le 0.54\mathrm{K}$. The data of the \kn\ crystal imply the presence of a large $T^2$ contribution to the specific heat which gives evidence of $d$-wave order parameter symmetry in the superconducting state. To improve the measurements, a novel design for a calorimeter with a paramagnetic temperature sensor is presented. It promises a temperature resolution of $\Delta T\approx 0.1\mu \mathrm{K}$ and an addenda heat capacity less than $200pJ/K$ at $T<100\mathrm{mK}$.

arXiv comment8 pages, 5 figures

References in corpus (5)

• Evidence of Strong Correlations and Coherence-Incoherence Crossover in the Iron Pnictide Superconductor KFe2As2
• Specific heat of the iron-based high-$T_c$ superconductor SmO${}_{1-x}$F${}_x$FeAs
• Specific heat and upper critical field in KFe2As2 single crystals
• The superconducting gaps in LiFeAs: Joint study of specific heat and ARPES
• Evidence of d-wave Superconductivity in K_(1-x)Na_xFe_2As_2 (x = 0, 0.1) Single Crystals from Low-Temperature Specific Heat Measurements

Cited by in corpus (2)

• Development of a novel calorimetry setup based on metallic paramagnetic temperature sensors
• Specific Heat of Holmium in Gold and Silver at Low Temperatures