Phase separation in A-site-ordered perovskite manganite LaBaMn2O6 probed by 139La and 55Mn NMR.
Phase separation in A-site-ordered perovskite manganite LaBaMn2O6 probed by 139La and 55Mn NMR.
复制标题
通过 139La 和 55Mn NMR 探测 A 位有序钙钛矿亚锰矿 LaBaMn2O6 中的相分离。
DOI：
10.1103/physrevlett.96.037202
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发表时间：
2005
影响因子：
8.6
通讯作者：
Y. Ueda
中科院分区：
文献类型：
--
作者：
Y. Kawasaki;T. Minami;Y. Kishimoto;T. Ohno;K. Zenmyo;H. Kubo;T. Nakajima;Y. Ueda
139La和55Mn-NMR谱表明，a位有序钙钛矿型锰矿LaBaMn2O6的基态是铁磁区和反铁磁区的空间混合物，分别属于金属有序态和绝缘电荷有序态。这种奇异的共存状态出现在200k以下，是通过铁磁金属内部反铁磁电荷有序态的类一阶态形成。Mn自旋-自旋弛豫速率表明，LaBaMn2O6中与反铁磁区共存的铁磁区与无序形式La0.5Ba0.5MnO3的块体铁磁金属相相同，尽管没有a位无序。这表明LaBaMn2O6中的铁磁区是介观性质而不是纳米性质。
139La- and 55Mn-NMR spectra demonstrate that the ground state of the A-site-ordered perovskite manganite LaBaMn2O6 is a spatial mixture of the ferromagnetic and antiferromagnetic regions, which are assigned to the metallic and the insulating charge ordered state, respectively. This exotic coexisting state appears below 200 K via a first-order-like formation of the antiferromagnetic charge ordered state inside the ferromagnetic metal one. The Mn spin-spin relaxation rate indicates that the ferromagnetic region coexisting with the antiferromagnetic one in LaBaMn2O6 is identical to the bulk ferromagnetic metal phase of the disordered form La0.5Ba0.5MnO3 in spite of the absence of A-site disorder. This suggests a mesoscopic rather than nanoscopic nature of the ferromagnetic region in LaBaMn2O6.