title: Commensurate spin dynamics in the superconducting state of an electron-doped cuprate superconductor.
abstract: We report neutron scattering studies on two single crystal samples of the electron-doped (n-type) superconducting (SC) cuprate Nd2-xCexCuO4 (x=0.15) with T(c)=18 and 25 K. Unlike the hole-doped (p-type) SC cuprates, where incommensurate magnetic fluctuations commonly exist, the n-type cuprate shows commensurate magnetic fluctuations at the tetragonal (1/2 1/2 0) reciprocal points both in the SC and in the normal state. A spin gap opens up when the n-type cuprate becomes SC, as in the optimally doped p-type La2-xSrxCuO4. The gap energy, however, increases gradually up to about 4 meV as T decreases from T(c) to 2 K, which contrasts with the spin pseudogap behavior with a T-independent gap energy in the SC state of p-type cuprates.
authors.affiliation: Institute for Chemical Research, Kyoto University, Uji 611-0011, Japan. yamada@scl.kyoto-u.ac.jp
authors.forename: K
authors.initials: K
authors.lastname: Yamada
authors.forename: K
authors.initials: K
authors.lastname: Kurahashi
authors.forename: T
authors.initials: T
authors.lastname: Uefuji
authors.forename: M
authors.initials: M
authors.lastname: Fujita
authors.forename: S
authors.initials: S
authors.lastname: Park
authors.forename: S H
authors.initials: SH
authors.lastname: Lee
authors.forename: Y
authors.initials: Y
authors.lastname: Endoh