Pomeranchuk effect in unstable Ytterbium systems

TL;DR

This paper demonstrates the presence of a Pomeranchuk effect in Ytterbium-based Kondo lattice materials, where entropy differences between phases suggest potential for novel cooling applications.

Contribution

It reveals the Pomeranchuk effect in Ytterbium systems and discusses their potential use as cooling devices, a novel insight in Kondo lattice physics.

Findings

Entropy of Fermi liquid phase is smaller than local moment phase along the coexistence line.

A Pomeranchuk effect analogous to $^3He$ is identified in Ytterbium systems.

Potential application as cooling machines is proposed.

Abstract

$YbInCu_{4}$ and its alloys present discontinuous, first order iso-structural transitions at pressure dependent temperatures $T_V(P)$, where a local moment phase coexist with a renormalized Fermi liquid phase. We show that along the coexistence line $T_V(P)$ the entropy of the large volume renormalized Fermi liquid phase is smaller than that of the higher density, local moment phase. This implies the existence of a Pomeranchuk effect in these Kondo lattice materials in analogy with $^3He$. The theoretical possibility of using these systems as cooling machines is discussed.