Magnetic Field Dependence of the Low-Temperature Specific Heat in PrInAg_2: Support for a Non-Magnetic Heavy-Fermion Ground State

TL;DR

This study investigates the low-temperature specific heat of PrInAg_2 under magnetic fields, providing evidence that its heavy-fermion ground state is non-magnetic, with the Kondo effect arising from hyperfine interactions rather than magnetic moments.

Contribution

The paper offers new insights into the non-magnetic nature of the Kondo effect in PrInAg_2 through detailed specific heat measurements and analysis of hyperfine interactions.

Findings

The specific heat anomaly peak shifts minimally with magnetic field.

A nuclear Schottky anomaly indicates hyperfine enhancement of Pr nuclei.

The insensitivity of the anomaly to magnetic fields supports a non-magnetic Kondo ground state.

Abstract

In order to elucidate the nature of the ground state in the heavy-electron system PrInAg_2, we measured its specific heat for temperatures between 60 mK and 2 K in magnetic fields up to 9 T. The peak maximum of the low temperature anomaly in the specific heat (interpreted as Kondo anomaly) shifts from 0.42 K at zero field to 0.45 K at 6 T, and to 0.5 K at 9 T. The data at 3 T (after subtracting the low temperature tail due to a Schottky anomaly) is practically indistinguishable from the zero field data. A low temperature nuclear Schottky anomaly from a hyperfine enhancement of the Pr nuclei was observed in field. Both enhanced hyperfine interaction and the insensitivity of the specific heat anomaly to fields support the hypothesis that the Kondo effect in this system has a non-magnetic origin.