Scaling of the physical properties in Ba(Fe,Ni)2As2 single crystals: Evidence for quantum fluctuations

Abstract

We report on local magnetization, tunnel diode oscillators, and specific-heat measurements in a series of Ba(NixFe1-x)2As2 single crystals (0.26\leqx\leq0.74). We show that the London penetration depth \lambda(T)=\lambda(0)+\Delta\lambda(T) scales as \lambda(0)\propto1/Tc0.85$\pm$0.2, \Delta\lambda(T)\proptoT2.3$\pm$0.3 (for T