Studies On The Colossal Magnetoresistance In Perovskite-manganese Oxides And Phase Relations Related With Manganese Oxides

In this paper, a series of bulk polycrystalline La_1-xK_xMnO₃(01-xK_xMnO₃ contained a single perovskite when x≤0.65, and were composed of two phases (a magnetic perovskite phase and a nonmagnetic KMnO₂ phase) for x>0.65. For x≥0.65 ,the lattice parameter irregularly changed with substituting K+ for La3+.2 Below the curie temperature the samples were ferromagnet, and a transition from ferromagnetic state to paramagnetic state was observed.3 At low temperature the samples were metallic state and with the temperature increasing a transition from metal to semiconductor was observed. The resistivity data fit equally well with three conducting mechanisms.4 The phase relations in the Bi₂O₃-Fe₂O₃-MnO_y ternary system were investigated by means of X-ray powder diffraction at room temperature .The compounds Bi₂5FeO₄0, Bi₁2MnO₂0, BiFeO₃, BiMn₂O₅, Bi₂Fe₄O₉ and FeMnO₃ were identified in this system. In this ternary system, there were seven three-phase regions and no ternary compounds were observed.