Fig. 7.

Specific heat measurements in fields from ${\mu }_{0}H=$ 0 T to 8 T in the vicinity of the superconducting phase transition, for three representatives samples: (A) the nearly optimally doped HEA ${\left[\text{TaNb}\right]}_{1-x}{\left(\text{ZrHfTi}\right)}_x$ with x = 0.33; (B) the HEA with x = 0.84, which has a upper critical field ${\mu }_0{H}_{\text{c}2}$ above the Pauli limit; and (C) the nearly optimally doped HEA ${\left[\text{TaNbV}\right]}_{1-x}{\left(\text{ZrHfTi}\right)}_x,$ which includes vanadium, with x = 0.33; the $T_{\text{c}}$ for this HEA is significantly lower than for the equivalent electron-count HEA where vanadium is not present.