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| Hauptseite > Publikationsdatenbank > Charge correlations in cobaltates La 2- x Sr x CoO 4 |
| Hauptseite > Publikationsdatenbank > Charge correlations in cobaltates La 2- x Sr x CoO 4 |
| Journal Article | FZJ-2016-00816 |
; ; ;
2015
Wiley-VCH
Weinheim
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Please use a persistent id in citations: doi:10.1002/pssr.201510290
Abstract: 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.
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