The influence of Cr doping on the charge-ordering state in bilayered LaSr2Mn2O7

摘要

The effect of Cr doping on the charge-ordered (CO) state of the bilayered manganite LaSr2Mn2O is investigated by electronic transport and magnetic property measurements. With Cr doping, the metal-insulator transition disappears and the temperature dependence of resistivity rho(T) exhibits semiconducting behavior. Both the antiferromagnetic transition temperature T-N and the CO temperature T-CO shift to lower temperature and the cluster glass state appears with increasing Cr doping level. The increase of resistivity and the slight change in the magnetization with increasing Cr content may be related to the combined effect of the partial destruction of the Mn-O-Mn interaction network within the ferromagnetic (FM) layers of an A-type antiferromagnet and the appearance of Cr3+-O-Mn3+ FM interaction. Additionally, the introduction of the random Coulomb potential caused by the substitution of Cr3+ for Mn3+ is also a source of increased resistivity. Both, the different effects of Mn-site doping on the CO state between the perovskite and layered manganites and the different effects of Co doping and Cr doping in the Mn site in layered manganites on the CO state are discussed. (C) 2004 American Institute of Physics.