中国物理B ›› 2004, Vol. 13 ›› Issue (6): 958-967.doi: 10.1088/1009-1963/13/6/030

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Phase separation and abnormal transport behaviours in La0.7-xGdxSr0.3MnO3 system

刘宁1, 童伟2, 张裕恒2   

  1. (1)Department of Physics, Suzhou Advanced Normal College, Suzhou 234000, China; Structure Research Laboratory, University of Science and Technology of China, Hefei 230026, China; (2)Structure Research Laboratory, University of Science and Technology of China, Hefei 230026, China
  • 收稿日期:2003-09-24 修回日期:2004-02-12 出版日期:2004-07-05 发布日期:2005-07-05
  • 基金资助:
    Project supported by the National Natural Science Foundation of China (Grant No 10334090) and the State Key Development Programme for Basic Research of China (Grant No 001CB610604).

Phase separation and abnormal transport behaviours in La0.7-xGdxSr0.3MnO3 system

Liu Ning (刘宁)ab, Tong Wei (童伟)b, Zhang Yu-Heng (张裕恒)b   

  1. a Department of Physics, Suzhou Advanced Normal College, Suzhou 234000, China; b Structure Research Laboratory, University of Science and Technology of China, Hefei 230026, China
  • Received:2003-09-24 Revised:2004-02-12 Online:2004-07-05 Published:2005-07-05
  • Supported by:
    Project supported by the National Natural Science Foundation of China (Grant No 10334090) and the State Key Development Programme for Basic Research of China (Grant No 001CB610604).

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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.

关键词: magnetic structure, phase separation, abnormal transport behaviours

Abstract: The magnetic and transport behaviours of the La$_{0.7-x}$Gd$_x$Sr$_{0.3}$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 $\rho$－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.

Key words: magnetic structure, phase separation, abnormal transport behaviours

中图分类号:  (Spin glasses and other random magnets)

  • 75.50.Lk
75.50.Ee (Antiferromagnetics) 75.30.Kz (Magnetic phase boundaries (including classical and quantum magnetic transitions, metamagnetism, etc.))