title: An x-ray scattering study of the structural phase transition in La(2-x)Sr(x)Cu0.99Fe0.01O4 (x = 0.20).
abstract: We report a comprehensive x-ray scattering study of the low-temperature orthorhombic (LTO)-high-temperature tetragonal (HTT) structural phase transition in 1% iron-doped La(2-x)Sr(x)CuO(4) (x = 0.2). The superlattice (032) peak intensity and the width are investigated in detail for a wide temperature range. We found that the structural phase transition is not sharp and the tilt ordering of the CuO(6) octahedra persists above the transition temperature T(S) (≈77 K). Even at room temperature, the superlattice peak is still observable. The structural phase transition is identified as an order-disorder type phase transition. We found that the tilt ordering in our iron-doped material is always short-ranged, and in the HTT phase the correlation between the tilts along the b axis is better preserved than that along the a axis. Moreover, we identify the role of the Fe as the nucleation centers of the LTO domains in the structural phase transition.
authors.affiliation: Materials Physics Laboratory, State Key Laboratory for Mesoscopic Physics, Department of Physics, Peking University, Beijing, People's Republic of China.
authors.forename: W T
authors.initials: WT
authors.lastname: Jin
authors.forename: H
authors.initials: H
authors.lastname: Gretarsson
authors.forename: M
authors.initials: M
authors.lastname: Fujita
authors.forename: C-Y
authors.initials: CY
authors.lastname: Kim
authors.forename: H
authors.initials: H
authors.lastname: Zhang
authors.forename: Young-June
authors.initials: YJ
authors.lastname: Kim