Synthesis and Orbital structure of structure- and valence-controlled layered manganites

结构和价态控制的层状锰酸盐的合成和轨道结构

• 批准号: 10440107
• 负责人: MORIMOTO Yutaka
• 金额: $ 8万
• 依托单位: Nagoya University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 1998
• 资助国家: 日本
• 起止时间: 1998 至 1999
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-10440107/
• 关键词: Doped manganites; Structure-control; Valence-control; Orbital physics; 層状ペロブスカイト型; 物質開拓

In the present project, we have systematically synthesized structure- and valence-controlled layered manganites, and have investigated their magnetotransport properties as well a magnetic and crystal structures. In the following, we list a major results obtained in this project.1. Ground state phase diagram for bilayer manganitesIn this system, we can control (a) formal valence of the Mn ions and (b) distortion of the Mn06 octahedra by means of chemical substitution. After a systematical crystal synthesis and measurements of their physical properties, we have experimentally derived the ground state phase diagram for bilayer manganites. We further have found a strong correlation between the magnetic structure and distortion of the Mn06 octahedra.2. Interrelation between orbital stability and magnetic structureWe have evaluated the orbital stability by calculation of the Madelung potential energy. We clearly have observed strong interrelation between the orbital stability and magnetic structure in the structure-controlled bilayer manganites at a fixed Mn valence (= +3.4). Therefore, in the bilayer manganites, chemical substitution affects the orbital stability. Making a sharp contrast with the other transition metal oxide systems.3. Direct observation of the orbital (in collaboration with Sakata group)We recently have succeed in visualizing the orbital state of bilayer manganites by means of MEM, which was developed by Sakata group at Nagoya University. We plan to start a project on this time, that is orbital physics, with getting some research fund.

在本项目中，我们系统地合成了结构和价态可控的层状锰氧化物，并研究了它们的磁输运性质以及磁性和晶体结构。在下文中，我们列出了在本项目中取得的主要成果。双层锰氧化物的基态相图在这个体系中，我们可以通过化学取代来控制（a）Mn离子的形式价态和（B）Mn O 6八面体的畸变。在系统的晶体合成和物理性质测量之后，我们从实验上导出了双层锰氧化物的基态相图。我们还发现了Mn 〇 6八面体的磁结构和畸变之间的强相关性。轨道稳定性与磁结构的相互关系我们通过计算马德隆势能来评估轨道稳定性。我们清楚地观察到在Mn原子价固定（= +3.4）的结构控制的双层锰氧化物中，轨道稳定性和磁结构之间存在很强的相关性。因此，在双层锰氧化物中，化学取代影响轨道稳定性。与其它过渡金属氧化物体系形成鲜明对比.轨道的直接观测（与Sakata小组合作）我们最近成功地通过MEM可视化双层锰氧化物的轨道状态，这是由名古屋大学的Sakata小组开发的。我们计划在这段时间启动一个项目，那就是轨道物理，并获得一些研究基金。

项目成果

Y. Moritomo: "Competition between the antiferromagnetic charge-orderd and ferromagnetic states in doped manganites"Phys Rev.. B60. 10374-10377 (1999)

Y. Moritomo：“掺杂锰矿中反铁磁电荷有序态和铁磁态之间的竞争”Phys Rev.. B60。

Y.Moritomo et al.: "Chemical Pressure control of spin-volve" Phys.Rev.B. 59. 印刷中 (1999)

Y. Moritomo 等人：“自旋旋转的化学压力控制”Phys.Rev.B. 出版中 (1999)

Y Moritomo, et al.: "Competiton of interbilayer magnetic coupling in Lal. 4Srl. 6Mn207"Phys Rev.. B59. 157-160 (1999)

Y Moritomo 等人：“Lal. 4Srl. 6Mn207 中双层间磁耦合的竞争”Phys Rev.. B59。

T.Akimoto,et al.: "Interrelation between the orbital polarization and magnetic structure in bilayer manganites"Phys.Rev.B. 59. R14153-R14156 (1999)

T.Akimoto 等人：“双层锰氧化物中轨道极化与磁性结构之间的相互关系”Phys.Rev.B。

Y. Moritomo, et al.: "Competition of interbilayer magnetic coupling in La1.4Sr1.6Mn207"Phys. Rev. B. 59. 157-160 (1999)

Y. Moritomo 等人：“La1.4Sr1.6Mn207 中双层间磁耦合的竞争”Phys。