Structural, magnetic and electrical properties of the La0.7Ca0.3Co1–xMnxO3（x=0, 0.7 and 1） samples prepared by a simple method were systematically studied and it was found that the crystal structure was transformed...Structural, magnetic and electrical properties of the La0.7Ca0.3Co1–xMnxO3（x=0, 0.7 and 1） samples prepared by a simple method were systematically studied and it was found that the crystal structure was transformed from rhombohedral for La0.7Ca0.3CoO3（LCCO） and La0.7Ca0.3Co0.3Mn0.7O3（LCCMO） samples to orthorhombic for La0.7Ca0.3MnO3（LCMO） sample. The AC magnetic susceptibility measurements showed that LCCO sample underwent a transition from paramagnetic（PM） to ferromagnetic（FM） phase at Curie temperature, TC^155 K and below Curie temperature, the glassy ferromagnetism nature was observed. In LCCMO sample,clear evidence of spin glass（SG） state was observed at low temperature. PM-FM phase transition at about TC^260 K and long range FM order at low temperatures were observed in LCMO sample. Both the LCCO and LCCMO samples exhibited insulating behavior in the whole range of measuring temperature whereas the LCMO sample underwent a clear metal-insulator（MI） transition at about TMI^263 K, corresponding to Curie temperature. Metallic region of ρ（T） curve of the LCMO sample was fitted to the model of electron-electron and electron-magnon scattering. The charge carrier transport behavior in all the samples was compared based on polaronic models.展开更多
基金the Payame Noor University for supporting this work
文摘Structural, magnetic and electrical properties of the La0.7Ca0.3Co1–xMnxO3（x=0, 0.7 and 1） samples prepared by a simple method were systematically studied and it was found that the crystal structure was transformed from rhombohedral for La0.7Ca0.3CoO3（LCCO） and La0.7Ca0.3Co0.3Mn0.7O3（LCCMO） samples to orthorhombic for La0.7Ca0.3MnO3（LCMO） sample. The AC magnetic susceptibility measurements showed that LCCO sample underwent a transition from paramagnetic（PM） to ferromagnetic（FM） phase at Curie temperature, TC^155 K and below Curie temperature, the glassy ferromagnetism nature was observed. In LCCMO sample,clear evidence of spin glass（SG） state was observed at low temperature. PM-FM phase transition at about TC^260 K and long range FM order at low temperatures were observed in LCMO sample. Both the LCCO and LCCMO samples exhibited insulating behavior in the whole range of measuring temperature whereas the LCMO sample underwent a clear metal-insulator（MI） transition at about TMI^263 K, corresponding to Curie temperature. Metallic region of ρ（T） curve of the LCMO sample was fitted to the model of electron-electron and electron-magnon scattering. The charge carrier transport behavior in all the samples was compared based on polaronic models.
