Inhomogeneous electronic structure probed by spin-echo experiments in the electron doped High-Tc superconductor Pr1.85Ce0.15CuO4-y -: art. no. 047003

C-63 nuclear magnetic resonance spin-echo decay rate (T-2(-1)) measurements are reported for the normal and superconducting states of a single crystal of Pr1.85Ce0.15CuO4-y in a magnetic field B-0=9 T over the temperature range 2<200 K. The spin-echo decay rate is temperature dependent for T<55 K and has a substantial dependence on the radio frequency (rf) pulse parameters below Tapproximate to25 K. This dependence indicates that T-2(-1) is strongly effected by a local magnetic field distribution that can be modified by the rf pulses, including ones that are not at the nuclear Larmor frequency. The low-temperature results are consistent with the formation of a static inhomogeneous electronic structure that couples to the rf fields of the pulses.