Incommensurate spin correlations in highly oxidized cobaltates La2−xSrxCoO4

نویسندگان

  • Z. W. Li
  • Y. Drees
  • C. Y. Kuo
  • H. Guo
  • A. Ricci
  • D. Lamago
  • O. Sobolev
  • U. Rütt
  • O. Gutowski
  • T. W. Pi
  • A. Piovano
  • W. Schmidt
  • K. Mogare
  • Z. Hu
  • L. H. Tjeng
  • A. C. Komarek
چکیده

We observe quasi-static incommensurate magnetic peaks in neutron scattering experiments on layered cobalt oxides La2-xSrxCoO4 with high Co oxidation states that have been reported to be paramagnetic. This enables us to measure the magnetic excitations in this highly hole-doped incommensurate regime and compare our results with those found in the low-doped incommensurate regime that exhibit hourglass magnetic spectra. The hourglass shape of magnetic excitations completely disappears given a high Sr doping. Moreover, broad low-energy excitations are found, which are not centered at the incommensurate magnetic peak positions but around the quarter-integer values that are typically exhibited by excitations in the checkerboard charge ordered phase. Our findings suggest that the strong inter-site exchange interactions in the undoped islands are critical for the emergence of hourglass spectra in the incommensurate magnetic phases of La2-xSrxCoO4.

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عنوان ژورنال:

دوره 6  شماره 

صفحات  -

تاریخ انتشار 2016