Magnetic-field dependence of the low-temperature specific heat in PrInAg2:: Support for a nonmagnetic heavy-fermion ground state

In order to elucidate the nature of the ground state in the heavy-electron system PrInAg2, 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) are 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 nonmagnetic origin. [S0163-1829(99)51410-0].