Magnetic ground state of CeNi$_{1-x}$Cu$_{x}$: A calorimetric investigation

TL;DR

This study investigates the magnetic ground state of CeNi$_{1-x}$Cu$_{x}$ using calorimetry, revealing inhomogeneous nanometric magnetic clusters and two interaction regimes, challenging the existence of a quantum critical point.

Contribution

It provides a comprehensive calorimetric analysis combined with previous studies to describe the inhomogeneous magnetic state and the percolative magnetic ordering process.

Findings

Identification of two regimes dominated by RKKY or Kondo interactions

Evidence for a percolative process of magnetic clusters below freezing temperature

Disproof of a quantum critical point at the magnetic-nonmagnetic crossover

Abstract

We present a detailed specific heat study of the CeNi$_{1-x}$Cu$_{x}$series in a large temperature range of 0.2 K to 300 K. The analysis of these data, considering also previous neutron scattering, magnetic characterization and $\mu$SR results, allows us to present a convenient description of the system as inhomogeneous on the nanometric scale. Two regimes are detected in the compositional range depending on the dominant RKKY or Kondo interactions. We propose that the long-range magnetic order at low temperatures is achieved by a percolative process of magnetic clusters that become static below the freezing temperature $T_{f}$. In this scenario the existence of a Quantum Critical Point at the magnetic-nonmagnetic crossover must be discarded.