Magnetic susceptibility, specific heat, and crystal-field effects in neodymium cuprate superconductors.

Abstract

We report here the results of magnetic susceptibility of both n- and p-type superconductors, ${\mathrm{Nd}}_{2\mathrm{\ensuremath{-}}\mathit{x}}$${\mathrm{Ce}}_{\mathit{x}}$${\mathrm{CuO}}_{4\mathrm{\ensuremath{-}}\mathit{y}}$ (x=0.14, 0.15, 0.16, and 0.18) and ${\mathrm{NdBa}}_{2}$${\mathrm{Cu}}_{3\mathrm{\ensuremath{-}}\mathit{z}}$${\mathrm{Zn}}_{\mathit{z}}$${\mathrm{O}}_{7\mathrm{\ensuremath{-}}\mathrm{\ensuremath{\delta}}}$ (z=0 and 0.02) in the temperature range 2 to 300 K and specific heat measurements on p-type superconductors in the temperature range 5\ensuremath{\le}T\ensuremath{\le}300 K. Crystal-field (CF) analysis of these results has been performed considering J mixing of the lowest eleven multiplets with intermediate-coupled wave functions. The CF analysis of the magnetic susceptibility data is consistent also with the reported inelastic neutron-scattering spectra. The specific heat data have been accounted for by considering Debye, Einstein, and Schottky contributions.