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Acta Chimica Sinica ›› 1995, Vol. 53 ›› Issue (11): 1065-1070. Previous Articles Next Articles
Original Articles
李思温;任玉芳
发布日期:
LI SIWEN;REN YUFANG
Published:
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Three new oxides Sm2SrCo2O7, Sm2BaCo2O7 and Gd2SrCo2O7 have been synthesized successfully by solid state reaction mathod. The X-Ray diffraction spectra show that they are all isostructural with Sr3Ti2O7, and Ln2SrCo2O7 (Ln=Sm, Gd) crystallized in tetragonal system, Sm2BaCo2O7 in orthrhombic system. The Co-O bonds in CoO2 planes of Ln2SrCo2O7 are shorter than those of LnSrCoO4 (Ln=Sm, Gd), and so their delectrons are more delocalized and their electrical resistivities are smaller. The electrical resistivities versus temperature in the range300-1100K showed that the five oxides show the characters of weakly localized systems. In the lower temperature range, the magnetic behaviors of Gd2SrCo2O7 and GdSrCoO4 fit Curie-Weiss law well, and the magnetic exchange reaction in CoO2 sublattices of Gd2SrCo2O7 is ferromagnetic, but that of GdSrCoO4 is antiferromagnetic. The other three oxides with Sm^3^+ showed complex magnetic behaviors which is perhaps related with the complexity of Sm^3^+.
Key words: COBALT OXIDE, BARIUM OXIDE, STRONTIUM OXIDE, CADMIUM OXIDE, PHASE STRUCTURE, MAGNETIZATION, SAMARIUM OXIDE, ELECTROMAGNETIC PROPERTIES
CLC Number:
O612
LI SIWEN;REN YUFANG. Studies on the synthetic, structural, electrical and magnetic properties of Ln~nMCo~nO~3n+1(Ln=Sm, GD; M=Sr, Ba; n=1,2)[J]. Acta Chimica Sinica, 1995, 53(11): 1065-1070.
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