INPLANE THERMAL-CONDUCTIVITY OF ND2-XCEXCUO4-Y

We present measurements of ab-plane thermal conductivity (kappa) for a series of Nd2-xCexCuO4-y single crystals (x=0.025,0.15,0.22) at T less-than-or-equal-to 300 K. For all specimens kappa increases with decreasing temperature, rises sharply for T < 100 K, and reaches a maximum at T=20-30 K. Near room temperature kappa almost-equal-to 12 W/mK for the insulator (x=0.025) and K almost-equal-to 14-16 W/mK in superconducting (x=0.15) and metallic (x=0.22) specimens. These differences are attributed to differing electronic contributions to heat conduction. No anomaly in kappa(T) was observed at the superconducting transition of the x=0.15 sample. For T < T(c), kappa is suppressed slightly by the application of a strong magnetic field, consistent with an increase in phonon-electron scattering. The kappa data are compared to previous results for the other cuprates.