Low-temperature specific heat of La0.67Ba0.33MnO3 and La0.8Ca0.2MnO3

We report measurements of the specific eat of La0.67Ba0.33MnO3 and La0.8Ca0.2MnO3 for temperatures 2<T<15 K. These materials are ferromagnetic metallic oxides which exhibit colossal magnetoresistance. We find that above 3 K the specific heat has terms proportional to T and T-3, but a T-3/2 term, as might be expected from the excitation of ferromagnetic spin waves, cannot be resolved outside of the precision of the data. The cubic term gives Debye temperatures of 400+/-17 K, and the linear term gives electron densities of states which are enhanced over band-structure estimates.