【摘要】 为了阐明在锰氧化物多晶以及外延薄膜中存在的低温电阻极小值现象,对La2/3Sr1/3MnO3单晶样品的性质进行研究.该单晶样品是利用光学浮区生长炉,在氩气气氛中生长出的高品质晶体,系统研究了退火对La2/3Sr1/3MnO3单晶低温输运行为的影响.结果表明,在退火前样品存在的低温电阻极小值无论是c轴还是ab平面在退火后均消失,这一结果首次证明了在锰氧化物体系中存在的低温电阻极小是一种非本征的物理行为,与实验样品的制备工艺和存在于其中的非完整性具有较强的依赖性,并进一步证明自旋无序散射乃是传统体系出现低温电阻极小的主要原因.更多还原

【Abstract】 In order to clarify the physical mechanism of the low-temperature resistivity minimum observed in polycrystal and epitaxy films of manganites,the single crystal La2/3Sr1/3MnO3 were studied,which were fabricated in Ar atmosphere by optical-floating-zone method. The transmission electron microscopy and the temperature dependence of resistivity were measured before and after annealing. The physical properties of the single crystal were markedly influenced by annealing treatment. The most interesting of all is the resistivity minimum at low temperature vanished after annealing treatment both along the c axis and a-b plane. Consequently,it is reasonable that the low-temperature resistivity minimum is an extrinsic phenomenon,which is caused from spin disorder scattering.更多还原