摘要
利用固相反应烧结法制备了La0 6 7Pb0 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( =3 5 3K)非常接近TMI( =3 60K) .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 ,T<TMI 时 ,低温区电阻率满足公式 ρ(T) =ρ0 +ρT2 5,此输运机理是由磁流子散射造成的 ;当T >TMI 时 。
Single-phase polycrystalline samples of La 0 67Pb 0 33MnO 3 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 T MI(=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)=ρ 0+ρT 2.5 for T<T MI, but agree with the polaron model when T>T MI. This phenomenon is due to the magon-carrier scattering.
出处
《物理学报》
SCIE
EI
CAS
CSCD
北大核心
2003年第5期1245-1249,共5页
Acta Physica Sinica
基金
高等学校重点实验室访问学者基金资助的课题~~
