Ordering of ferromagnetic Mn–Mn dimers vs. Mn3+/Mn4+ charge ordering in the Pr1-xCaxMnO3 (x≈0.5) perovskites
Ordering of ferromagnetic Mn–Mn dimers vs. Mn3+/Mn4+ charge ordering in the Pr1-xCaxMnO3 (x≈0.5) perovskites
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Pr1-xCaxMnO3 (x≈0.5) 钙钛矿中铁磁 Mn-Mn 二聚体的排序与 Mn3+/Mn4+ 电荷排序的比较
DOI：
10.1007/s003390101270
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发表时间：
2002
期刊：
影响因子：
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通讯作者：
A. Revcolevschi
中科院分区：
文献类型：
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作者：
A. Daoud;J. Rodríguez;L. Pinsard;M. Fernández;A. Revcolevschi
Pr 1-xCaxMnO 3（x ≤ 0.5）锰氧化物在低于转变温度TCO时显示出电子局域化以及调制的结构畸变。它通常归因于电荷和轨道有序（CO/OO），这是由合作Jahn-Teller效应和库仑相互作用驱动的纯电子过程。然而，一个不受约束的结构细化从中子衍射实验低于TCO的Pr0.60Ca0.40MnO3单晶，给我们一个结构，其扭曲邀请我们重新考虑过渡的微观机制。这一结果有力地表明，过渡有一个磁结构的起源，与TCO以下的铁磁对的形成。在这种情况下，这些类型的化合物的电子定位和磁性重新解释。
The Pr1-xCaxMnO3(x≈0.5) manganites display an electronic localization together with a modulated distortion of the structure below a transition temperature TCO. It is commonly attributed to charge and orbital ordering (CO/OO), which are purely electronic processes driven by the cooperative Jahn–Teller effect and the Coulomb interaction. However, an unconstrained structure refinement from a neutron-diffraction experiment below TCOon a Pr0.60Ca0.40MnO3single crystal, gives us a structure whose distortions invite us to reconsider the microscopic mechanism of the transition. The result strongly suggests that the transition has a magneto-structural origin, associated with the formation of ferromagnetic pairs below TCO. The electronic localization and the magnetic properties of these types of compounds are re-interpreted in this context.