Specific Heat Measurements of Ce_1−xLa_xB₆

Abstract

Specific heat measurements have been done on the samples of Ce_1−xLa_xB₆ (x=0, 0.03, 0.10 and 0.25) at low temperatures down to 0.1 K under the magnetic field of 0, 6 and 36 kOe. In the ordered state specific heat consists of a T³-term and a large γT-term. The former originates from the excitation of antiferromagnetic spin wave and the latter is common in the dense Kondo systems. The γ-value is insensitive to the La-doping and the applied magnetic field as well as the type of magnetic ordering. The result is consistent with the Γ₈ ground level model but with a substantial distortion. The present result is also consistent with the temperature dependence of resistivity in the same temperature range.