La0.67Pb0.33MnO3的磁性及输运特性

利用固相反应烧结法制备了La067Pb033MnO3单相多晶样品.研究了其结构、磁性及输运特性.结果表明，样品呈菱面相晶体结构，空间群为R3C，居里温度TC(=353K)非常接近TMI(=360K).在居里温度附近，发生铁磁-顺磁转变，导电特性由金属特征向半导体特征过渡.磁电阻在居里点达到极大值.当H=16T时，磁电阻的极大值为145%；当H=08T时，磁电阻的极大值为9%.输运性质表明，TTMI时关键词：磁电阻输运特性磁极化子钙钛石

Magnetic and transport properties of perovskite La0.67Pb0.33MnO3

Single phase polycrystalline samples of La067Pb033MnO3 were prepared by conventional solid state reaction method. The crystal structure and magnetic and transport properties are investigated. The structure revealed by the room temperature x ray powder diffraction is rhombohedral(R3C), and the Curie temperature is very close to TMI(=360K). At the Curie point, the magnetic properties show the transition from ferromagnetic to paramagnetic, and the conductivity changes from metal to semiconducting. The resistivity decreases with increasing magnetic field. Magnetoresistance reaches a maximum at the Curie point. The maximum magnetoresistance is 14^5% at H=1^2MA/m, and 9% at H=0^6MA/m. The transport results show that the transport data satisfy ρ(T)=ρ0+ρT2.5 for TTMI. This phenomenon is due to the magon carrier scattering.