Acta Phys. -Chim. Sin. ›› 1999, Vol. 15 ›› Issue (01): 44-49.doi: 10.3866/PKU.WHXB19990109

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Mixed Doping and Nonstoichiometry Effect in Manganate

Zhang Jian-Hui, Zhu Chang-Fei, Li Ya-Dong, Li Xiao-Guang   

  1. Department on Materials Science and Engineering,University of Science and Technology of China,Hefei 230026|Laboratory of Institute Friction and Defects in Solid Academia Sinica,University of Science and Technology of China,Hefei 230026|Department of Chemistry,University of Science and Technology of China,Hefei 230026
  • Received:1998-03-09 Revised:1998-07-20 Published:1999-01-15
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Abstract:

The microstructure and electric conduction variations in compounds Nd0.67Sr0.33-xBaxMnO3(x=0.27, 0.165, 0.06) and Nd0.67SrxBaxMnOz(x=0.27, 0.06) were studied. It was found that the conduction mechanism of Nd0.67Srx.Ba0.33-xMnO3 doped by mixed divalent ions differs from that of Nd0.67Sr0.33 MnO3 or Nd0.67Ba0.33MnO3 doped by single divalent ions. Due to the lattice contraction induced by nonstoichimetry, the resistivity reduces obviously and the resistivity transition (I-M) appears with decreasing temperature in Nd0.67SrxBaxMnOz. In addition, it was found that the lattice contraction induced by the nonstoichiometry on Mn site is larger than that on A site.

Key words: Mixed doping, Nonstoichiometry, Lattice contraction, Electric conduction