%0 Journal Article
%A Guo, H.
%A Schmidt, W.
%A Tjeng, L. H.
%A Komarek, A. C.
%T Charge correlations in cobaltates La 2- x Sr x CoO 4
%J Physica status solidi / Rapid research letters
%V 9
%N 10
%@ 1862-6254
%C Weinheim
%I Wiley-VCH
%M FZJ-2016-00816
%P 580 - 582
%D 2015
%X Nano-phase separation in La2–xSrx CoO4 (schematically). Red areas: undoped La2CoO4 islands, blue areas: checkerboard charge ordered regions; black, green and blue balls represent nonmagnetic Co3+ ions, magnetic Co2+ ions and oxygen ions, respectively; green arrows indicate Co2+ spins [1, 2].We report on an elastic neutron scattering study of the charge correlations in La2–xSrx CoO4 with x = 1/3, 0.4 and 0.5. We found that the checkerboard charge ordering correlations present in the x = 0.5 sample persist in the x = 0.4 and 1/3 materials. These checkerboard charge ordering correlations are robust and explain the occurrence of nano-phase separation in layered cobaltates for Sr-concentrations away from half-doping. The half-integer reflections then arise from the nanometer-sized hole-rich regions (blue areas in title figure) instead of the undoped ones (red areas in title figure). The appearance of nano-phase separation is an important ingredient for understanding the formation of hour-glass shaped magnetic excitation spectra in La2–xSrx CoO4.
%F PUB:(DE-HGF)16
%9 Journal Article
%U <Go to ISI:>//WOS:000363266800005
%R 10.1002/pssr.201510290
%U https://juser.fz-juelich.de/record/281111