2007/08/31 by S. R. Dunsiger, Yang Zhao, Y. Zhao +5 · 1 citation
Materials Science · Physics and Astronomy · #Advanced Condensed Matter Physics #Magnetic and transport properties of perovskites and related materials #Physics of Superconductivity and Magnetism #cond-mat.str-el #cond-mat.supr-con
paper · pdf · doi:10.1103/physrevb.77.224410
9 pages, 7 figures, submitted to PRB, figures updated
arxiv created 2008/03/20 · openalex publication_date 2008/06/05 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/28
By using neutron scattering techniques, we have studied the incommensurate spin ordering as well as the low energy spin dynamics in single crystal underdoped La_2\ensuremath-xBaxCuO4 with x\ensuremath∼0.095 and 0.08, which are high temperature superconductors with TC\ensuremath∼27 and 29 K, respectively. Static two dimensional incommensurate magnetic order appears below TN=39.5\ifmmode±\else\textpm\fi0.3 K in La_2\ensuremath-xBaxCuO4 (x=0.095) and a similar temperature for x=0.08 within the low temperature tetragonal phase. The spin order is unaffected by either the onset of superconductivity or the application of magnetic fields of up to 7 T applied along the c axis in the x=0.095 sample. Such a magnetic field independent behavior is in marked contrast to the field induced enhancement of the staggered magnetization observed in the related La_2\ensuremath-xSrxCuO4 system, which indicates that this phenomenon is not a universal property of cuprate superconductors. Surprisingly, we find that the incommensurability \ensuremathδ is only weakly dependent on doping relative to La_2\ensuremath-xSrxCuO4. Dispersive excitations in La_2\ensuremath-xBaxCuO4 (x=0.095) at the same incommensurate wave vector persist up to at least 60 K. The dynamical spin susceptibility of the low energy spin excitations saturates below TC in a similar manner to that seen in the superconducting state of La2CuO4+y.