Structures and electromagnetic properties of new metal-ordered manganites:: RBaMn2O6 (R = Y and rare-earth elements)
Structures and electromagnetic properties of new metal-ordered manganites:: RBaMn2O6 (R = Y and rare-earth elements)
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DOI：
10.1143/jpsj.71.2843
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发表时间：
2002-12-01
影响因子：
1.7
通讯作者：
Ueda, Y
中科院分区：
文献类型：
--
作者：
Nakajima, T;Kageyama, H;Ueda, Y
根据测量的结构和电磁性能，可以将新型金属有序锰氧化物RBaMn2O6分为三类。第一组(R=Tb，Dy和Ho)表现出三个相变，即冷却时的结构相变、电荷/轨道相变(CO)和反铁磁相变(AF)，如YBaMn2O6中观察到的。第二组(R=Sm，Eu和Gd)表现出CO相变，然后是AF相变。第三组(R=La，Pr和ND)在PrBaMn2O6和NdBaMn2O6中表现出金属铁磁相变和A型AF相变。与金属无序(R(0.5)(3+)A(0.5)(2+))MnO_3相比，RBaMn2O6具有两个显著的特点：(1)在340K以上具有较高的CO转变温度(TCO)；这与MnO2亚晶格夹有RO和BaO两种不同晶格大小的岩盐层的构造特征密切相关。
New metal-ordered manganites RBaMn2O6 can be classified into three groups based on the structural and electromagnetic properties measured. The first group (R = Tb, Dy and Ho) shows three successive phase transitions, namely, structural, charge/orbital order (CO) and antiferromagnetic order (AF) transitions on cooling, as observed in YBaMn2O6. The second group (R = Sm, Eu and Gd) exhibits a CO transition, followed by an AF transition. The third group (R = La, Pr and Nd) exhibits a metallic ferromagnetic transition, followed by an A-type AF transition in PrBaMn2O6 and NdBaMn2O6. Compared with metal-disordered (R(0.5)(3+)A(0.5)(2+))MnO3, RBaMn2O6 has two remarkable features: (1) the high CO transition temperature (Tco) above 340 K and (2) the presence of a structural transition above Tco in the first group. These are closely related to the structural feature that the MnO2 sub-lattice is sandwiched by two types of rock-salt layers, RO and BaO, with different lattice sizes.