Synchrotron X-ray Magnetic Scattering Studies under Strong Magnetic Fields

强磁场下同步加速器X射线磁散射研究

• 批准号: 14204037
• 负责人: KATSUMATA Koichi
• 金额: $ 29.87万
• 依托单位: The Institute of Physical and Chemical Research
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (A)
• 财政年份: 2002
• 资助国家: 日本
• 起止时间: 2002 至 2004
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-14204037/
• 关键词: Synchrotron magnetic X-ray diffraction; Field induced magnetic phase transitions; Strong magnetic fields; Highly correlated electron systems; Quantum spin systems; Spin-Peierls transition; Low carrier materials; 放射光X線磁気散乱; 高濃度近藤物質; 多極子秩序; 反強磁性体

In this project, we aim at clarifying the magnetic and structural changes in quantum magnetic systems under high magnetic fields using synchrotron X-ray diffraction technique. Some of the outstanding findings obtained from this project are briefly described below.(1)We have found that the incommensurability in the high field phase of a spin-Peierls compound, CuGeO_3 depends much on temperature near the critical field (〓12 T), while at high enough field it is independent of temperature. We have interpreted that this finding is due to a stabilization of the incommensurate state by a strong magnetic field which suppresses thermal fluctuations.(2)At the critical field from the spin liquid to a long-range ordered phase of a spin 1/2 ladder compound Cu_2(C_5H_<12>N_2)_2Cl_4,one expects a generalized spin-Peierls transition, in which a lattice distortion is predicted to occur. We have performed X-ray diffraction study on a single crystal of this compound at the World's lowest temperature of 0.04 K and at high fields. We have found that the lattice constant along the a-axis shows a discontinuous change at the critical field.(3)Synchrotron X-ray diffraction measurements have been performed on CeP which is a typical example of dense Kondo systems despite its small carrier concentration. In CeP two layers of Γ_8 like Ce and a layer of Γ_7 like Ce are stacked with a period which changes with an applied magnetic field. From our study performed in high fields up to 14 T we have discovered new phases with 8 and 9 periods.(4)We are successful in developing a pulsed high field for synchrotron X-ray diffraction. We have constructed a split pair magnet capable of producing pulsed field up to 35 T without destruction and measured X-ray diffraction on some compounds.

本计画的目的是利用同步辐射X光绕射技术，探讨量子磁性系统在强磁场下的磁性与结构变化。下文简要介绍了该项目取得的一些突出成果。(1)We发现CuGeO_3的高场不稳定性在临界场（~ 12 T）附近与温度有很大关系，而在足够高的场下与温度无关。我们解释说，这一发现是由于稳定的无公度状态的强磁场，抑制热波动。(2)At从自旋为1/2的梯形化合物Cu_2（C_5H_N_2）_2Cl_4的自旋液体到长程有序相的临界场<12>，我们预测了一个广义的自旋Peierls转变，在这个转变中，晶格畸变将发生。我们在世界最低温度0.04K和高场条件下对该化合物的单晶进行了X射线衍射研究。我们发现，晶格常数沿着a轴在临界场处呈现不连续的变化。（3）对CeP进行了同步辐射X射线衍射测量，CeP是致密近藤系统的典型例子，尽管它的载流子浓度很小。在CeP中，两层类Γ_8的Ce和一层类Γ_7的Ce以随外加磁场变化的周期堆叠。从我们在高达14 T的高场进行的研究中，我们发现了8和9个周期的新相位。(4)We成功地开发了用于同步辐射X射线衍射的脉冲高场。我们已经建立了一个分裂对磁体能够产生高达35 T的脉冲场而不破坏和测量的X射线衍射对一些化合物。

项目成果

Direct and quantitative determination of the orbital ordering in CeB_6 by X-ray diffraction

X 射线衍射直接定量测定 CeB_6 中的轨道有序度

• 发表时间: 2004
• 期刊: Europhysics Letters 68
• 作者: Y.Tanaka;U.Staub;K.Katsumata;S.W.Lovesey;J.E.Lorenzo;Y.Karumi;V.Seagnoli;S.Shimomura;Y.Tabata;Y.Onuki;Y.Kuramoto;A.Kikkawa;T.Ishikawa;H.Kitamura
• 通讯作者: H.Kitamura

本多善太郎: "The Spin Gap in a Quantum Antiferromagnet on the Kagome Lattice"Journal of Physics ; Condensed Matter. 14,38. L625-L629 (2002)

Zentaro Honda：“戈薇晶格上的量子反铁磁体的自旋间隙”，《凝聚态物理》杂志 14,38（2002 年）。

High Magnetic Fields, Science and Technology Theory and Experiments I

强磁场、科技理论与实验Ⅰ

• 发表时间: 2003
• 作者: Ogino;T.;勝又紘一(分担執筆)
• 通讯作者: 勝又紘一(分担執筆)

勝又紘一(分担執筆): "High Magnetic Fields Science and Technology Theory and Experiments I"World Scientific. 271 (2003)

Koichi Katsumata（撰稿人）：“高磁场科学技术理论与实验 I”World Scientific 271（2003）。

鳴海康雄: "The Coexistence of Magnetic Phases at the First-Order Phase Transition of a Metamagnet FeCl_2・2H_2O Studied by X-ray Diffraction"Journal of Physics : Condensed Matter. 16,7. L57-L63 (2004)

Yasuo Narumi：“通过 X 射线衍射研究超磁体 FeCl_2·2H_2O 的一阶相变中磁相的共存”物理学杂志：凝聚态物质 16,7。