Phonon density of states in La sub (1.85) Sr sub (.15) CuO sub 4.

Specific heat and inelastic neutron scattering studies of the high-T sub C superconducting compound La sub (1.85) Sr sub (.15) CuO sub 4 are reported. A distinct anomaly of electronic origin in the specific heat is found at the superconducting transition temperature. The phonon density of states up to ~20 meV is extracted from both experiments and the two sets of results agree well in yielding a sharply enhanced density of states at 10 meV, in accord with a recent theoretical study.