Direct imaging of doped fluorine in LaFeAsO1-xFx superconductor by atomic scale spectroscopy

Tohei, Tetsuya; Mizoguchi, Teruyasu; Hiramatsu, Hidenori; Kamihara, Yoichi; Hosono, Hideo; Ikuhara, Yuichi
November 2009
Applied Physics Letters;11/9/2009, Vol. 95 Issue 19, p193107
Academic Journal
We report direct observation of fluorine ion dopants in the recently discovered LaFeAsO1-xFx superconductor, where the doping is critical for the superconductivity. Employing spectroscopic imaging based on scanning transmission electron microscopy, the spatial distribution of the doped fluorine ions, which are invisible in Z-contrast imaging, is clearly visualized with atomic-scale resolution. The observation directly proves that fluorine substitutes into the oxygen site in the superconducting LaFeAsO1-xFx compound. Our results demonstrate the potential of the present method for revealing dopants undetectable by conventional microscopy imaging.


Related Articles

  • Contrasting Effects of Ca2+ and Ho3+ Substitutions on Superconductivity and Excess conductivity of (Ho1-xCax)(Ba2-yHoy)Cu3O7-δ. Maulud, M. F.; Hamidi, Z. S.; Yusof, A. A.; Yusof, M. I. M.; Yahya, A. K. // AIP Conference Proceedings;7/7/2010, Vol. 1250 Issue 1, p504 

    Effects of Ho3+ and Ca2+ substitutions in (Ho1-xCax)(Ba2-yHoy)Cu3O7-δ ceramics on normal and superconducting state behaviour were investigated. Electrical resistivity measurements showed increasing Ho3+ substitution at Ba2+ site (x = 0, 0.4, y = 0-0.4) caused normal state resistivity to...

  • Excess Conductivity Analysis and the Critical Region in Be-Doped CuTlBaCaBeCuZnO Superconductors. Rahim, M.; Ullah, Kefayat; Khan, Nawazish // Journal of Superconductivity & Novel Magnetism;Jun2012, Vol. 25 Issue 4, p975 

    The excess conductivity analysis of as-prepared and oxygen-annealed Be-doped CuTlBaCaBe(CuZn)O ( y=0, 0.15, 0.3, 0.45) superconducting samples is carried out in the critical regimes and beyond. Various superconducting parameters, like the zero resistance critical temperature T, mean field...

  • Superconductivity in fluorine and yttrium co-doped SmFeAsO. Lai, K. T.; Kwong, F. L.; Ng, Dickon H. L. // Journal of Applied Physics;May2012, Vol. 111 Issue 9, p093912 

    Polycrystalline fluorine and yttrium co-doped SmFeAsO samples are synthesized by solid state sintering and their physical properties are studied. The lattice parameters of the Sm1-yYyFeAsO0.8F0.2 samples decrease with the increasing y due to the smaller Y ions and the stiffness of the Y-O bond....

  • Two-component scenario, cuprate related gaps, and superconducting density. Kristoffel, Nikolai; Rubin, Pavel // Proceedings of the Estonian Academy of Sciences, Physics, Mathem;Jun2005, Vol. 54 Issue 2, p98 

    A simple model of cuprate superconductivity with an electron spectrum prepared by doping is developed. The pair-transfer interaction couples the itinerant band with two components ("hot" and "cold") of the defect subsystem. Basic defect-itinerant gaps are quenched by progressive doping. Band...

  • Role of Mobile Charge Carriers and Fluctuation Induced Conductivity in (CuTlK)BaCaCuZnO Superconductor. Mumtaz, M.; Khan, Nawazish A.; Hasnain, S. M.; Younis, Adnan // Journal of Superconductivity & Novel Magnetism;Aug2011, Vol. 24 Issue 6, p1939 

    The main role played by mobile carriers and fluctuation induced conductivity (FIC) in (CuTlK)BaCaCuZnO ( x=0, 0.25) superconductor samples are analyzed in the light of the Aslamazov-Larken (AL) theory. The enhancement of three-dimensional (3D) conductivity and grain size is achieved with...

  • Effect of Y Doping on Superconductivity and Spin-Density-Wave States in Sm1− xY xFeAsO0.8F0.2 and Sm1− xY xFeAsO. Chen, Y. L.; Cui, Y. J.; Cheng, C. H.; Yang, Y.; Zhang, Y.; Zhao, Y. // Journal of Superconductivity & Novel Magnetism;Jul2010, Vol. 23 Issue 5, p621 

    Y doping effects on crystal structure, resistivity, superconductivity, and spin-density-wave states in the parent and F-doped SmFeAsO compounds have been studied. Y doping leads to shrinkage of the lattice parameters in both systems. The superconductivity of Sm1− xY xFeAsO0.8F0.2 is...

  • Effect of Co Substitution on the Structure and Superconducting Properties of GaSr(Tm,Ca)CuO. Lee, H. // Journal of Superconductivity & Novel Magnetism;Jul2011, Vol. 24 Issue 5, p1381 

    The crystal structures of two samples with nominal compositions of GaSr(TmCa)CuO and (GaCo)Sr(TmCa)CuO have been analyzed by using neutron powder diffraction techniques to clarify the structural mechanisms associated with changes in superconducting behavior. Unlike for the Co-free sample, which...

  • Topology of the superconducting order under pairing repulsion. Belyavsky, V. I.; Kopaev, Yu. V.; Nguyen, N. T.; Tran, V. L. // Journal of Experimental & Theoretical Physics;Feb2009, Vol. 108 Issue 2, p301 

    The superconducting state with a large momentum of a pair in a doped insulator is controlled by the features of Coulomb pairing associated with the suppression of small momentum transfers during scattering owing to electron-phonon interaction and of large transfers due to redistribution of the...

  • Measuring Magnetoresistance in a 2D Intergranular Magnetic-Semiconducting Material. Ballestar, A.; Araujo, C.; Delatorre, R.; Pasa, A.; Garcia, N. // Journal of Superconductivity & Novel Magnetism;Nov2009, Vol. 22 Issue 8, p737 

    A new 2D intergranular semiconducting-magnetic material obtained by depositing magnetic clusters of permalloy in a doped Si surface, is presented. The material, exhibiting ohmic contacts, has an ample range of properties and versatility by simply controlling deposition time. We can have clusters...


Read the Article


Sorry, but this item is not currently available from your library.

Try another library?
Sign out of this library

Other Topics