Elastic properties of double layered manganites R_(1.2)Sr_(1.8)Mn_2O_7(R=La, Pr, Nd, Sm)  

作　　者：Yanala Srinivasa Reddy Puram Kistaiah Cholleti Vishnuvardhan Reddy 

机构地区：[1]Department of Physics, Chaitanya Bharathi Institute of Technology [2]Department of Physics, Osmania University

出　　处：《Rare Metals》2014年第2期166-170,共5页稀有金属（英文版）

摘　　要：The polycrystalline colossal magnetoresistive double-layered manganite samples R1.2Sr1.8Mn2O7（R = La Pr, Nd, Sm） were prepared by the sol–gel method and their room temperature elastic behavior was investigated by ultrasonic pulse transmission technique at 1 MHz. The values of elastic constants were calculated from longitudinal and shear velocities and they were corrected to zero porosity using Hasselman and Fulrath＇s formulae. The elastic constants of the samples were also estimated by Modi＇s heterogeneous metal-mixture rule which is based on the metal ions present in the samples. The measured,corrected, and estimated values of elastic moduli are found to increase with decreasing rare earth ion size. The variation of elastic moduli with the size of the rare earth ion is interpreted in terms of strength of interatomic bonding.The polycrystalline colossal magnetoresistive double-layered manganite samples R1.2Sr1.8Mn2O7（R = La Pr, Nd, Sm） were prepared by the sol–gel method and their room temperature elastic behavior was investigated by ultrasonic pulse transmission technique at 1 MHz. The values of elastic constants were calculated from longitudinal and shear velocities and they were corrected to zero porosity using Hasselman and Fulrath＇s formulae. The elastic constants of the samples were also estimated by Modi＇s heterogeneous metal-mixture rule which is based on the metal ions present in the samples. The measured,corrected, and estimated values of elastic moduli are found to increase with decreasing rare earth ion size. The variation of elastic moduli with the size of the rare earth ion is interpreted in terms of strength of interatomic bonding.

关 键 词：Elastic properties Porosity Sound velocity Magnetoresistance Manganites 

分 类 号：TQ133.3[化学工程—无机化工]