Universal behavior of CePd$_{1-x}$Rh$_x$ Ferromagnet at Quantum Critical Point

The heavy-fermion metal $\mathrm{CePd_{1-x}Rh_x}$ can be tuned from ferromagnetism at $x=0$ to non-magnetic state at some critical concentration $x_c$. The non-Fermi liquid behavior (NFL) at $x\simeq x_c$ is recognized by power low dependence of the specific heat $C(T)$ given by the electronic contribution, susceptibility $\chi(T)$ and volume expansion coefficient $\alpha(T)$ at low temperatures: $C/T\propto\chi(T)\propto\alpha(T)/T\propto1/\sqrt T$. We also demonstrate that the behavior of normalized effective mass $M^*_N$ observed in $\mathrm{CePd_{1-x}Rh_x}$ at $x\simeq0.8$ agrees with that of $M^*_N$ observed in paramagnetic $\rm CeRu_2Si_2$ and conclude that these alloys exhibit the universal NFL thermodynamic behavior at their quantum critical points. We show that the NFL behavior of $\mathrm{CePd_{1-x}Rh_x}$ can be accounted for within frameworks of quasiparticle picture and fermion condensation quantum phase transition, while this alloy exhibits a universal thermodynamic NFL behavior which is independent of the characteristic features of the given alloy such as its lattice structure, magnetic ground state, dimension etc.