Unusual Single-Ion Non-Fermi Liquid Behavior in Ce_(1-x)La_xNi_9Ge_4

TL;DR

This study investigates the non-Fermi liquid behavior in Ce_(1-x)La_xNi_9Ge_4, revealing unprecedented specific heat and magnetic properties that challenge conventional Fermi liquid theory, across various doping levels.

Contribution

It provides the first detailed analysis of single-ion non-Fermi liquid behavior in Ce_(1-x)La_xNi_9Ge_4, highlighting its unique properties and scaling behavior.

Findings

Record-high electronic specific heat c/T at 0.08K in CeNi_9Ge_4

Logarithmic increase of c/T below 3K in doped samples

Fermi liquid-like magnetic susceptibility below 1K in doped samples

Abstract

We report on specific heat, magnetic susceptibility and resistivity measurements on the compound Ce_(1-x)La_xNi_9Ge_4 for various concentrations ranging from the stoichiometric system with x=0 to the dilute limit x=0.95. Our data reveal single-ion scaling with the Ce-concentration and the largest ever recorded value of the electronic specific heat c/T approximately 5.5 J K^(-2)mol^(-1) at T=0.08K for the stoichiometric compound x=0 without any trace of magnetic order. While in the doped samples c/T increases logarithmically below 3K down to 50mK, their magnetic susceptibility behaves Fermi liquid like below 1K. These properties make the compound Ce_(1-x)La_xNi_9Ge_4 a unique system on the borderline between Fermi liquid and non-Fermi liquid physics.