The interplay of charge order and magnetism in Sr14Cu24O41 and Sr13LaCu24O41

Abstract We examined the doping dependence of the charge order in the spin chains of Sr 14 Cu 24 O 41 and Sr 13 LaCu 24 O 41 by 63 Cu-NMR. In Sr 14 Cu 24 O 41 we verified the existence of two distinct Zhang–Rice copper sites on the chains with a dimer local susceptibility in agreement with the macroscopic susceptibility. In Sr 13 LaCu 24 O 41 one broad line associated with a Zhang–Rice site is observed. In contrast to expectations motivated by the charge order model this signal also exhibits a thermally activated local susceptibility.