Localized moments and the stability of antiferromagnetic order in Yb3Pt4

TL;DR

This study investigates the magnetic and electronic properties of Yb3Pt4, revealing a field-induced suppression of antiferromagnetic order, B/T scaling due to paramagnetic fluctuations, and the absence of non-Fermi-liquid behavior, highlighting its simple f-electron regime.

Contribution

The paper provides detailed experimental insights into the magnetic phase transition and fluctuation effects in Yb3Pt4, emphasizing its simple f-electron behavior and minimal Kondo interaction.

Findings

Antiferromagnetic order collapses at 1.85 T with a first-order transition.

B/T scaling indicates dominance of paramagnetic fluctuations.

Fermi liquid behavior persists up to the phase boundary, no non-Fermi-liquid behavior observed.

Abstract

We present here the results of electrical resistivity {\rho}, magnetization M, ac susceptibility \c{hi}ac', and specific heat CM measurements that have been carried out on single crystals of Yb3Pt4 over a wide range of fields and temperatures. The 2.4-K N\'eel temperature that is found in zero field collapses under field to a first-order transition TN=0 at BCEP=1.85 T. In the absence of antiferromagnetic order, the specific heat CM(T,B), the magnetization M(T,B), and even the resistivity {\rho}(T,B) all display B/T scaling, indicating that they are dominated by strong paramagnetic fluctuations, where the only characteristic energy scale results from the Zeeman splitting of an energetically isolated, Yb doublet ground state. This paramagnetic scattering disappears with the onset of antiferromagnetic order, revealing Fermi liquid behavior {\Delta}{\rho}=AT2 that persists up to the antiferromagnetic phase line TN(B), but not beyond. The first-order character of TN=0 and the ubiquity of the paramagnetic fluctuations imply that non-Fermi-liquid behaviors are absent in Yb3Pt4. In contrast to heavy fermions such as YbRh2Si2, Yb3Pt4 represents an extremely simple regime of f-electron behavior where the Yb moments and conduction electrons are almost decoupled, and where Kondo physics plays little role.