晶粒尺寸对Pr_(0.5)(Ca_(0.47)Ba_(0.03))MnO_3中台阶效应的影响  

GRAIN SIZE EFFECT ON THE MULTISTIP-LIKE BEHAVIOR IN Pr_(0.5)(Ca_(0.47)Ba_(0.03))MnO_3

作　　者：王芳[1] 方军[1] 黄真[1] 张勇[1] 陈治友[1] 陈敬林[1] 

机构地区：[1]中国科学院等离子体物理研究所强磁场实验室,合肥230031

出　　处：《低温物理学报》2006年第1期26-30,共5页Low Temperature Physical Letters

摘　　要：采用溶胶-凝胶法制备了不同颗粒尺寸的Pr0.5(Ca0.47Ba0.03)MnO3多晶样品.对样品进行电阻测量发现,随颗粒边界的减小,其电阻率随磁场的变化即ρ(H)曲线上台阶数目和位置发生变化;实验同时发现,热循环对样品低温下的基态也有很大的影响.实验结果表明,颗粒尺寸大小,可以有效地调节反铁磁相(AFM)和铁磁相(FM)之间的相互作用,从而对台阶效应产生影响.进一步证明了台阶效应与相应力有关.Polycrystalline Pr0.5（Ca0.47Ba0.03）MnO3 was prepared by a sol-gel method After annealed at different temperatures TA, samples with different grain size were obtained. It was found that the grain size increases with TA. We conducted resistivity measurements with the sweeping field range of 0 ～7T. It was revealed that the reduction of the grain boundaries can dramatically affect the multistep behavior in Pr0.5（Ca0.47Ba0.03）MnO3. The experimental results also suggest that the changing of annealing temperature is an effective way to adjusting the interaction between the antiferromagnetic （AFM） phases and ferromagnetic （FM） phases in these samples, then affecting the step-like transition. Hence, it was proved that the interfacial strain between the two states plays an important role in the multistep-like transition.

关 键 词：钙钛矿锰氧化物 超大磁电阻效应 马氏体效应 边界效应 

分 类 号：O611.3[理学—无机化学]