Novel structures and electromagnetic properties of the A-site-ordered/disordered manganites RBaMn2O6/R0.5Ba0.5MnO3 (R = Y and rare earth elements)
Novel structures and electromagnetic properties of the A-site-ordered/disordered manganites RBaMn2O6/R0.5Ba0.5MnO3 (R = Y and rare earth elements)
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DOI：
10.1088/0953-8984/16/11/002
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发表时间：
2004-03
期刊：
影响因子：
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通讯作者：
Y. Ueda;T. Nakajima
中科院分区：
文献类型：
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作者：
Y. Ueda;T. Nakajima
综述了A位有序/无序锰钙钛矿RBaMn 2 O 6 /R0.5Ba0.5MnO3（R = Y和稀土元素）。RBaMn 2 O 6具有显著的特征：（1）在远高于300 K的较高温度下的电荷/轨道序（CO）转变，（2）沿c轴沿着具有四倍周期性的CE型CO的新的堆积变化，（3）可能伴随dx 2 -y2轨道序的结构转变，（4）电子相分离.这些新的结构和电磁性能的MnO 2正方形亚晶格夹在两种类型的岩盐层，RO和BaO，具有不同的晶格尺寸的结构特性进行了讨论。这种结构对MnO 2亚晶格引入了强烈的阻挫效应，对电荷、轨道、自旋和晶格之间的多自由度竞争产生了新的扰动。在R 0.5 Ba 0.5 MnO 3与原始立方钙钛矿电池，另一方面，磁性玻璃态占主导地位的基态。在Pr0.5Ba0.5MnO3中观察到一种特殊的行为，即阶梯状的超尖锐磁化强度和电阻率变化.
The A-site-ordered/disordered manganese perovskites, RBaMn 2 O 6 /R 0.5 Ba 0.5 MnO 3 (R = Y and rare earth elements), are reviewed. RBaMn 2 O 6 displays remarkable features: (1) the charge/orbital order (CO) transition at relatively high temperatures far above 300 K, (2) a new stacking variation of the CE-type CO with a fourfold periodicity along the c-axis, (3) the presence of structural transition possibly accompanied by d x 2 -y 2 orbital order and (4) electronic phase segregation. These novel structural and electromagnetic properties are discussed in terms of the structural characteristic that the MnO 2 square sublattice is sandwiched by two types of rock-salt layer, RO and BaO, with different lattice sizes. Such structure introduces a strong frustration to the MnO 2 sublattice and gives a new perturbation to the competition of multiple degrees of freedom among charge, orbital, spin and lattice. In R 0.5 Ba 0.5 MnO 3 with a primitive cubic perovskite cell, on the other hand, the magnetic glassy states are dominant as the ground state. A peculiar behaviour, steplike ultrasharp magnetization and resistivity changes, has been observed in Pr 0.5 Ba 0.5 MnO 3 .