the search of the orbital ordering of the magnetic moment by using x-ray magnetic scattering

利用X射线磁散射寻找磁矩的轨道排序

• 批准号: 09440128
• 负责人: ENDOH Yasuo
• 金额: $ 9.09万
• 依托单位: Tohoku University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 1997
• 资助国家: 日本
• 起止时间: 1997 至 1998
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-09440128/
• 关键词: orbital ordering; x-ray magnetic scattering; ATS scattering; Jahn Teller effect; synchrotron radiation; manganites; neutron scattering; lift of orbital; Tahn-Teller効果

We have studied the "high temperature superconductivity " and /or "colossal magnetoresistance (CMR)" as the key phenomena in the strongly correlated electron systems. In order to explore this important issue, we initiated to investigate a novel degree of freedom of "order" by using new technique of the synchrotron x-ray scattering besides neutron scattering.First we studied carefully the mechanism of the resonant x-ray scattering of the orbital order occurred at the energy of K edge of the magnetic metal element, actually Mn cations. Then we found the mechanism that the intra Coulomb interaction between 4p and 3d orbital which is in the orbital ordered state lifts the 4p degeneracy. Then it gives rise an enhancement or resonance. Then we deeply studied the orbital order in LaMnO_3 originated by the Jahn Teller effect by using this newly established technique of the synchrotron x-ray scattering.Second, we also extend this technique to study the phase transition of metal insulator in the doped manganites as recognized the CMR materials. We found that the phase transition is triggered by the orbital order-disorder transition.Third, we extend this project studied during the recent two years granted to a new project aiming the standard probe of studying the orbital fluctuations.

我们研究了“高温超导”和/或“巨磁阻（CMR）”作为强相关电子系统中的关键现象。为了探索这一重要问题，我们开始利用除中子散射之外的同步加速器X射线散射新技术来研究一种新的“有序”自由度。轨道有序发生在磁性金属元素（实际上是Mn阳离子）的K边缘能量处。然后我们发现了处于轨道有序状态的4p和3d轨道之间的库仑内相互作用提升了4p简并性的机制。然后它会产生增强或共鸣。然后我们利用这种新建立的同步加速器X射线散射技术，深入研究了由Jahn Teller效应引起的LaMnO_3中的轨道序。其次，我们还将该技术扩展到研究掺杂锰氧化物中金属绝缘体的相变。 CMR 材料。我们发现相变是由轨道有序-无序转变引发的。第三，我们将近两年研究的项目延伸到一个新的项目，旨在研究轨道涨落的标准探针。

项目成果

Y.Endoh et al.: "Colossal Magnetoresistive Oxides in Advances in condensed Matter Science, "Review of Spin Dynamics and Orbital Ordering"" Elsevier. 432 (1999)

Y.Endoh 等人：“凝聚态科学进展中的巨型磁阻氧化物，“自旋动力学和轨道排序综述””爱思唯尔。

K.Yamada, C.H.Lee, et al.: "Doping dependance of the Spacially modulated dynamical spin Correlations and Superconductiong thansition" :Physicak Review B. (印刷中).

K. Yamada、C. H. Lee 等人：“空间调制动态自旋相关性和超导比的掺杂依赖性”：Physicak Review B.（出版中）。

K.Hirota, Y.Endoh et al.: "Magnetic excitations of bandwidth-controlled Mn Perovskite (La_<1-x-y>Y_y) Sr_xMnO_3" J.Magn.Magn.Mater.177-181. 864-866 (1998)

K.Hirota、Y.Endoh 等人：“带宽控制的 Mn 钙钛矿 (La_<1-x-y>Y_y) Sr_xMnO_3 的磁激发”J.Magn.Magn.Mater.177-181。

Y.Endoh, T.Fukuyama, K.Nakajima, K.Kakurai: "Polariyed Neutron Studies for Cr Excitations" J.Phys.Soc.Jpn.66・6. 1615-1617 (1997)

Y.Endoh、T.Fukuyama、K.Nakajima、K.Kakurai：“Cr 激发的极化中子研究”J.Phys.Soc.Jpn.66・6（1997）。

H.Fujioka, K.Hirota, Y.Endoh et al.: "Spin Dynamical Properties of the Layered Perovskite La_<1.2>Sr_<1.8>Mn_2O_7" J.Phys.Chem.Solid. (in press).

H.Fujioka、K.Hirota、Y.Endoh 等人：“层状钙钛矿 La_<1.2>Sr_<1.8>Mn_2O_7 的自旋动力学特性”J.Phys.Chem.Solid。