Specific heat and magnetic susceptibility of superconducting and semiconducting ${\mathrm{Nd}}_{1.85}$${\mathrm{Ce}}_{0.15}$${\mathrm{CuO}}_{4\mathrm{-}\mathrm{\delta }}$

Specific-heat (${\mathit{C}}_{\mathit{p}}$) data in the range of 0.4–20 K for a polycrystalline specimen of ${\mathrm{Nd}}_{1.85}$ ${\mathrm{Ce}}_{0.15}$ ${\mathrm{CuO}}_{4\mathrm{-}\mathrm{\delta }}$, in the superconducting state (δ=0.02) and on the same specimen, after annealing in air, in the semiconducting state (δ=0.0), are reported. Below 10 K, ${\mathit{C}}_{\mathit{p}}$ in ${\mathrm{Nd}}_{1.85}$ ${\mathrm{Ce}}_{0.15}$ ${\mathrm{CuO}}_{4\mathrm{-}\mathrm{\delta }}$, for both δ=0.02 and 0.0, is dominated by a Schottky anomaly. The Schottky anomaly has an entropy S within 5% of the R ln3 value. Limiting values for the Debye temperature, ${\mathit{FTHETA}}_{\mathit{D}}^0$ of 409±20 and 445±20 K are obtained in ${\mathrm{Nd}}_{1.85}$ ${\mathrm{Ce}}_{0.15}$ ${\mathrm{CuO}}_{4\mathrm{-}\mathrm{\delta }}$ for δ=0.02 and 0.0, respectively. Magnetic-susceptibility (κ) data in the range 2–280 K show that superconducting ${\mathrm{Nd}}_{1.85}$ ${\mathrm{Ce}}_{0.15}$ ${\mathrm{CuO}}_{4\mathrm{-}\mathrm{\delta }}$, undergoes a superconducting transition at 22 K. Above 40 K, κ in ${\mathrm{Nd}}_{1.85}$ ${\mathrm{Ce}}_{0.15}$ ${\mathrm{CuO}}_{4\mathrm{-}\mathrm{\delta }}$, for both δ=0.02 and 0.0, exhibits Curie-Weiss behavior, which is consistent with a material that displays antiferromagnetic coupling.