中国物理B ›› 2004, Vol. 13 ›› Issue (6): 958-967.doi: 10.1088/1009-1963/13/6/030
刘宁1, 童伟2, 张裕恒2
Liu Ning (刘宁)ab, Tong Wei (童伟)b, Zhang Yu-Heng (张裕恒)b
摘要: The magnetic and transport behaviours of the La_{0.7-x}Gd_xSr_{0.3}MnO_3 (0≤x≤0.70) system are investigated. The experimental results indicate that with increasing Gd doping content, the magnetism of the system changes from the long-range ferromagnetic order state to the cluster-spin glass state, then to the antiferromagnetic (AFM) state. It is interesting that the phase separation appears at x=0.30 and 0.40 and disappears for x≥0.50 where the AFM state occurs. At high doping content, the transport behaviours exhibit abnormality, e.g. there are two temperature ranges in which the ρ-T curves can be well fitted by a variable-range hopping (VRH) model. We suggest that the VRH does not come from the hopping of carriers between clusters, but from the different magnetic backgrounds in the clusters.
中图分类号: (Spin glasses and other random magnets)