title: Electron microscope studies of nano-domain structures in Ru-based magneto-superconductors: RuSr(2)Gd(1.5)Ce(0.5)Cu(2)O(10-delta) (Ru-1222) and RuSr(2)GdCu(2)O(8) (Ru-1212).
abstract: Microstructures of the RuSr(2)Gd(1.5)Ce(0.5)Cu(2)O(10-delta) (Ru-1222) and RuSr(2)GdCu(2)O(8) (Ru-1212) magneto-superconductors have been investigated by using selected-area electron diffraction, convergent-beam electron diffraction, dark-field electron microscopy and high-resolution electron microscopy at room temperature. Both Ru-1212 and Ru-1222 consist of nm-size domains stacked along the [Formula: see text] direction, where the domains are formed by two types of superstructures due to ordering of rotated RuO(6) octahedra about the c-axis. In Ru-1212, both primitive-and body-centered tetragonal superstructures (the possible space groups: P4/mbm and I4/mcm) are derived to form the corresponding nm-domains. It is of great interest that Ru-1212 consists of domains of two crystallographically different superstructures, while the similar domains observed in Ru-1222 have crystallographically identical superstructure with an orthorhombic symmetry (possible space group: Aeam), related by 90 degrees rotation around the c-axis (Yokosawa et al., 2003, submitted for publication).
authors.affiliation: Advanced Materials Laboratory, National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan. yokosawa.tadahiro@nims.go.jp
authors.forename: Tadahiro
authors.initials: T
authors.lastname: Yokosawa
authors.forename: V P S Veer Pal Singh
authors.initials: VP
authors.lastname: Awana
authors.forename: Koji
authors.initials: K
authors.lastname: Kimoto
authors.forename: Eiji
authors.initials: E
authors.lastname: Takayama-Muromachi
authors.forename: Maarit
authors.initials: M
authors.lastname: Karppinen
authors.forename: Hisao
authors.initials: H
authors.lastname: Yamauchi
authors.forename: Yoshio
authors.initials: Y
authors.lastname: Matsui