Low Temperature Thermodynamic Properties of the Heavy Fermion Compound YbAgGe Close to the Field-Induced Quantum Critical Point

TL;DR

This study investigates the low-temperature thermodynamic behavior of YbAgGe near its field-induced quantum critical point using heat capacity and magnetization measurements down to 50 mK and up to 11.5 Tesla.

Contribution

It provides detailed thermodynamic data that clarify the phase diagram and the nature of quantum criticality in YbAgGe, distinguishing the quantum critical point from magnetic saturation effects.

Findings

Electronic degrees of freedom drive observed features.

Refined boundaries of the H-T phase diagram.

Quantum critical point is separate from magnetic saturation.

Abstract

We present temperature and field dependent heat capacity and magnetization data taken at temperatures down to 50 mK and in an applied magnetic field up to 11.5 Tesla for YbAgGe, a heavy-fermion compound with a field induced quantum critical point. These data clearly indicate that the same electronic degrees of freedom are responsible for the features seen in both specific heat and magnetization data. In addition, they further refine the different boundaries suggested for the H - T phase diagram of YbAgGe through previous, magneto-transport measurements, and allow for further understanding of different phases on the H - T phase diagram, in particular, clearly disconnecting the field-induced quantum critical point in YbAgGe from any sort of saturation of the Yb moment in higher applied magnetic field.