Specific heat of heavy-fermion CePd2Si2 in high magnetic fields

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 similar to 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 a-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 dependences of both T-N and the magnetic entropy at T-N scale as [1 - (B/B-0)(2)] for B parallel to a, suggesting the disappearance of antiferromagnetism at B-0 similar to 42 T. The expected suppression of the antiferromagnetic transition temperature to zero makes the existence of a magnetic quantum critical point possible.