Doping dependence of the specific heat of single crystal BaFe$_{2}$(As$_{1-x}$P$_{x})_{2}$

We present a systematic study of the specific heat transitions on a series of BaFe$_{2}$(As$_{1-x}$P$_{x})_{2}$ single crystals with phosphorous doping ranging from near optimum doped x = 0.3 to strongly over doped x = 0.55. Our results reveal that BaFe$_{2}$(As$_{1-x}$P$_{x})_{2}$ follows the scaling \textit{$\Delta $C/T}$_{c }\sim \quad T_{c}^{2}$ remarkably well.\footnote{S. L. Bud'ko, N. Ni, P. C. Canfield, Phys. Rev. B \textbf{79}, 220516 (2009).} The clean-limit nature of this material imposes new restraints on theories aimed at explaining the scaling. We find that the Ginzburg-Landau parameter decreases significantly with doping whereas the superconducting anisotropy is $\Gamma \sim $2.6, independent of doping.