Universal behavior of $\rm CePd_{1-x}Rh_x$ Ferromagnet at Quantum Critical Point

TL;DR

This paper demonstrates that the heavy-fermion alloy $ m CePd_{1-x}Rh_x$ exhibits universal non-Fermi liquid thermodynamic behavior at its quantum critical point, independent of its specific lattice or magnetic properties.

Contribution

It shows that the NFL behavior in $ m CePd_{1-x}Rh_x$ aligns with other heavy-fermion systems and can be explained by quasiparticle and fermion condensation theories.

Findings

NFL behavior characterized by $C/T$, $ ext{susceptibility}$, and $ ext{volume expansion}$ follows a $1/\sqrt{T}$ dependence.

Normalized effective mass $M^*_N$ matches that of $ m CeRu_2Si_2$, indicating universality.

NFL behavior is independent of lattice structure, magnetic ground state, and dimensionality.

Abstract

The heavy-fermion metal $\rm CePd_{1-x}Rh_x$ 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, magnetic 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 $\rm CePd_{1-x}Rh_x$ at $x\simeq 0.8$ 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 $\rm CePd_{1-x}Rh_x$ 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.