Magnetic and Electrical Properties of Bi1−xSrxMnO3: Hole-Doping Effect on Ferromagnetic Perovskite BiMnO3

摘要: Although La3+and Bi3+ions have similar ionic radii, the Bi1−xSrxMnO3system was found to show quite different behavior from La1−xSrxMnO3in which ferromagnetism with metallic conductivity is achieved by “double exchange mechanism.” BiMnO3which synthesized under high pressure a ferromagnetic insulator withTc=105 K, in contrast antiferromagnetic LaMnO3. Though Sr substitution BiMnO3increased conductivity, no state up solid solution limit ofx=0.67. Furthermore saturation magnetic moment of 3.6μBobserved BiMnO3decreased very rapidly increasingx, and disappeared forx>0.4. These observations suggest that highly polarizable Bi3+ion 6s2lone pair would cause local distortion perovskite lattice, presumably reduces mobility carriers. The origin BiMnO3requires mechanism other than double theory.