Specific heat of heavy fermion CePd2Si2 in high magnetic fields

TL;DR

This study investigates the specific heat of heavy fermion CePd2Si2 under high magnetic fields, revealing how magnetic field orientation influences the antiferromagnetic transition and suggesting a potential quantum critical point at high fields.

Contribution

It provides detailed measurements of specific heat in CePd2Si2 under magnetic fields, highlighting anisotropic effects and the scaling behavior of transition temperature and entropy, indicating a possible quantum critical point.

Findings

Antiferromagnetic transition shifts with magnetic field orientation.

Maximum in gamma_0 at about 6 T correlates with susceptibility anomaly.

Scaling of T_N and entropy suggests antiferromagnetism vanishes near 42 T.

Abstract

We report specific heat measurements on the heavy fermion compound CePd2Si2 in magnetic fields up to 16 T and in the temperature range 1.4-16 K. A sharp peak in the specific heat signals the antiferromagnetic transition at T_N ~ 9.3 K in zero field. The transition is found to shift to lower temperatures when a magnetic field is applied along the crystallographic a-axis, while a field applied parallel to the tetragonal c-axis does not affect the transition. The magnetic contribution to the specific heat below T_N is well described by a sum of a linear electronic term and an antiferromagnetic spin wave contribution. Just below T_N, an additional positive curvature, especially at high fields, arises most probably due to thermal fluctuations. The field dependence of the coefficient of the low temperature linear term, gamma_0, extracted from the fits shows a maximum at about 6 T, at the point where an anomaly was detected in susceptibility measurements. The relative field dependence of both T_N and the magnetic entropy at T_N scales as [1-(B/B_0)^2] for B // a, suggesting the disappearance of antiferromagnetism at B_0 ~ 42 T. The expected suppression of the antiferromagnetic transition temperature to zero makes the existence of a magnetic quantum critical point possible.