TY  - JOUR
AU  - Guo, H.
AU  - Schmidt, W.
AU  - Tjeng, L. H.
AU  - Komarek, A. C.
TI  - Charge correlations in cobaltates La 2- x Sr x CoO 4
JO  - Physica status solidi / Rapid research letters
VL  - 9
IS  - 10
SN  - 1862-6254
CY  - Weinheim
PB  - Wiley-VCH
M1  - FZJ-2016-00816
SP  - 580 - 582
PY  - 2015
AB  - 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.
LB  - PUB:(DE-HGF)16
UR  - <Go to ISI:>//WOS:000363266800005
DO  - DOI:10.1002/pssr.201510290
UR  - https://juser.fz-juelich.de/record/281111
ER  -