OBSERVATION OF CONDUCTION ELECTRON-SPIN-RESONANCE IN THE ND1.85CE0.15CUO4-Y SUPERCONDUCTOR

Normal and superconducting Nd2-xCexCuO4-y (x - 0.00, 0. 15) compounds have been studied by electron spin resonance (ESR). In contrast to previous reports that the high-temperature superconducting oxocuprate compounds are ESR silent, a conduction ESR (CESR) signal has been observed in the superconducting Nd1.85Ce0.15CuO4-y compound. The temperature dependence of the CESR signal intensity, g value, and line width are consistent with a two-dimensional spin structure in Nd1.85Ce0.15CuO4-y. A possible reason for the lack of a CESR signal in other high-temperature superconducting systems is that they have more efficient spin-lattice relaxation which is associated with CESR lines too broad to be detected.