High Resolution Neutron Powder Diffraction Study of the Tubular Phase Bi 4 Sr 8 Cu 5 O 19+x
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HIGH RESOLUTION NEUTRON POWDER DIFFRACTION STUDY OF THE PHASE Bi4SraCu5Oi9+x. J.M.Navarro M.T.Caldds , J RodriguezC.Miravitlles J .Gonz~lez-Calbet
,
A.Futes Carvajal
TUBULAR
X, Obradors and M.Vallet
Institut de Ciencia de Materials de Barcelona (CSIC), C/Martl i Franquds s/n, 08028 BARCELONA, SPAIN Langevin, 156X, 38042 Grenoble Institut Max Von Laue-Paul CEDEX, France. (RENFE-UCM),28290 Las de Magnetismo Aplicado Laboratorio Matas, Madrid, Spain. ABSTRACT has powder diffraction experiment A high resolution neutron is well been performed on Bi4SreCu5Ois+x. The structure atoms in the described in the space group Fmmm with the oxygen in intermediate positions bismuth planes appearing disordered occurs in the and bridging sites as between NaCl dependence B izSrzCan-iCunO4n+z. Temperature superconductors between 1.5K diffraction patterns study of powder neutron change neither and 998K does not show any relevant structural of antiferromagnetic ordering in this sample. evidence INTRODUCTION Bi4Sr9Cu5Oi9-x is
to a non-superconducting oxide closely related structures of both Bi2Sr2CuO6. The crystal phases are based on the stacking of multiple perovskite and Bi-O perovskite layers, but in Bi4SreCuOso0+x the presence of extra the layers stacked perpendicularly to the Cu02 planes breaks high two-dimensional character of the structure, common to all figure l).Recently we (see Tc superconducting copper oxides determination of this reported the crystal structure have of compound by single crystal X-ray diffraction, and the study of electron the structural and physical properties by means ")Sr (CV)• the superconducting
Sr"(03) %
°o
BI(Sr-Cu)
$ (Cu) & co do0 &) 4b4b C do qb
)Sr (CU) Bi(Sr-cu) B1(Sr-Cu) Sr" (Cu)
(b)
(a) FIG.1
(a)
Perspective view of
the
cation
sublattice
copper-oxygen framework of Bi4SraCu50Ot+x. Mat. Res. Soc. Symp. Proc. Vol. 169. ©1990 Materials Research Society
and
(b)
134
microscopy, electrical resistivity and magnetic susceptibility [1,2]. Here we present the investigation of the exact location of neutron by means structure in the of the oxygen atoms results of these diffraction experiments, and the comparison with the superconducting phases in the Bi-Sr-Ca-Cu-O system. EXPERIMENTAL mixing by thoroughly Around 15g of sample were prepared heating then appropiate amounts of Bi2Cu04, SrCuO2 and SrCz04, 0 powder was then in air for 48 hours at 900 C. The reacted 120 pressed into a pellet and reannealed in air at 900 C for X-ray powder regrindings. intermediate hours with several amount of diffraction of this sample showed up a very small experiments diffraction Neutron SrCuO2 as an impurity phase. powder were performed at 1.5k and 300K on the high resolution A neutron powder diffractometer D2B at the I.L.L in Grenoble. 300 diffraction experiment as a function of temperature between and 998k was perfomed at the high flux powder diffractometer D1B also at the I.L.L.The analysis of the data was performed using was refinement structure program[3].The the STRAP package atomic coordinates previo
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