Specific heat jump at the superconducting transition temperature in Ba(Fe(1-x)Cox)2As2 and Ba(Fe(1-x)Nix)2As2 single crystals

摘要

We present detailed heat capacity measurements for Ba(Fe(1-x)Cox)2As2 andBa(Fe(1-x)Nix)2As2 single crystals in the vicinity of the superconductingtransitions. The specific heat jump at the superconducting transitiontemperature (Tc), Delta Cp/Tc, changes by a factor ~ 10 across these series.The Delta Cp/T$ vs. Tc data of this work (together with the literature data forBa(Fe0.939Co0.061)2As2, (Ba0.55K0.45)Fe2As2, and (Ba0.6K0.4)Fe2As2) scale wellto a single log-log plot over two orders of magnitude in Delta Cp/Tc and overabout an order of magnitude in Tc, giving Delta Cp/Tc ~ Tc^2.