Tuning A-site ionic size in R0.5Ca0.5MnO3 (R = Pr, Nd and Sm): robust modulation in dc and ac transport behavior
Tuning A-site ionic size in R0.5Ca0.5MnO3 (R = Pr, Nd and Sm): robust modulation in dc and ac transport behavior
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DOI：
10.1088/0953-8984/23/49/495902
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发表时间：
2011-12
期刊：
影响因子：
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通讯作者：
A. Karmakar;S. Majumdar;S. Giri
中科院分区：
文献类型：
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作者：
A. Karmakar;S. Majumdar;S. Giri
Pr0.5Ca0.5MnO3，Nd0.5Ca0.5MnO3和Sm0.5Ca0.5MnO3的结构研究显示，由于A位离子尺寸的变化，出现了正交畸变的系统调谐。使用各种模型对直流传导进行的全面调查表明，与结构变化有很强的相关性。作为频率和温度的函数的交流电导率机制的仔细分析带来了极化子传导机制的结构修改的显着效果。与典型的表现相反，直流电导率和电荷载流子的弛豫揭示了非Arrhenius行为。本工作提供了一个详细的和系统的除了在稀土锰氧化物系统的电子输运相图掺杂的二价碱金属原子。
Structural investigations on Pr0.5Ca0.5MnO3, Nd0.5Ca0.5MnO3 and Sm0.5Ca0.5MnO3 display a systematic tuning in orthorhombic distortion which appears due to a change in A-site ionic size. Comprehensive investigations on dc conduction using various models indicate strong correlation with structural changes. Careful analysis of the ac conductivity mechanism as a function of frequency and temperature brings out a pronounced effect of structural modifications on the polaron conduction mechanism. Contrary to typical manifestations, dc conductivity and relaxation of charge carriers reveal non-Arrhenius behavior. This work provides a detailed and systematic addition to the phase diagram of electronic transport in the rare-earth manganite system doped with a divalent alkali atom.