Neutron and x-ray diffraction study of the SrCr_8Ga_4O_(19) kagome compound synthesized by citrate route

摘要

SrCr_8Ga_4O_(19) (SCGO) has the magnetoplumbite structure with part of the Cr~(3=) (S chemical bounds 3/2) moments lying on the kagome layers (12K sites) separated by Cr~(3+) triangular layers (rf and 2a sites) [1, 2]. The strong geometric frustration of the magnetic sublattice gives a high degeneracy of the ground state that is the origin of particular low temperature properties. The magnetic sublattice is diluted by a partial interchange of the Cr and Ga atoms that has been observed in all structural refinements published up to now. This dilution affects the magnetic properties and therefore it is important to investigate the Cr/Ga distribution in this system, as well as the synthesis conditions that control the structural properties.