Development of high precision THz-ESR system by using repealing pulsed magnetic fields

利用相斥脉冲磁场开发高精度太赫兹-ESR系统

• 批准号: 13554011
• 负责人: NOJIRI Hiroyuki
• 金额: $ 9.02万
• 依托单位: OKAYAMA UNIVERSITY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 2001
• 资助国家: 日本
• 起止时间: 2001 至 2003
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-13554011/
• 关键词: Ultra-high magnetic fields; Extreme condition; ESR; Terahertz wave; Pulsed magnetic fields; 繰り返しパルス磁場; 強磁場; テラヘルツ; ナノ磁性体; サブミリ波

A high precision terahertz ESR system has been developed by using a repeating pulsed magnetic field. The system is capable of generating pulsed magnetic fields up to 30 T every two seconds. The drastic improvement of signal to noise ratio is achieved by the signal averaging technique. The ratio becomes at least 50 times higher than that of the conventional ESR spectrometer by using a single shot type pulse field. The maximum frequency up to 3 THz can be used and it is extremely higher than that of the commercial W-band ESR spectrometer. Moreover, the efficiency defined by the possible number of scans par unit time is much larger than that of ESR spectrometer using superconducting magnets. The typical resolution of the present system is 10 gauss in simple hardware averaging method. The resolution ca be improved to 1 gauss by using a software averaging by suing a peak picking process. Test experiments have been made on a ladder compound and a micro single crystal of nano-magnetic cluster. Even a very weak forbidden transition can be observed by present system. The present result leads to the application of a repeating pulsed magnetic field for various types of spectroscopy such as Raman scattering or X-ray spectroscopy for solid state.

利用重复脉冲磁场，研制了高精度太赫兹电子自旋共振系统。该系统能够每两秒产生高达30T的脉冲磁场。信噪比的大幅度提高是通过信号平均技术实现的。使用单次激发型脉冲场，这一比率比传统的ESR光谱仪提高了至少50倍。最高频率可达3太赫兹，远远高于市售W波段电子自旋共振波谱仪。此外，单位时间内可能的扫描次数所定义的效率比使用超导磁体的ESR光谱仪要大得多。在简单的硬件平均方法下，该系统的典型分辨率为10高斯。采用峰值拾取过程，用软件求平均值，可将分辨率提高到1高斯。对梯形化合物和纳米磁性团簇的微单晶进行了测试实验。在目前的系统中，甚至可以观察到非常弱的禁忌跃迁。本结果导致重复脉冲磁场应用于各种类型的光谱，例如用于固态的拉曼散射或X射线光谱。

项目成果

M.Motokawa, H.Ohta, H.Nojiri: "The role of ESR in research of low dimensional antiferromagnet"J.Phys.Soc.Jpn.. 72.Suppl.B. 1-11 (2003)

M.Motokawa、H.Ohta、H.Nojiri：“ESR 在低维反铁磁体研究中的作用”J.Phys.Soc.Jpn.. 72.Suppl.B。

T.Sakon, K.Koyama, M.Motokawa, H.Nojiri, T.Asano, Y.Ajiro: "Electron spin resonance measurement at ultralow temperatures"Physica B. 329-333. 1629-1631 (2003)

T.Sakon、K.Koyama、M.Motokawa、H.Nojiri、T.Asano、Y.Ajiro：“超低温下的电子自旋共振测量”Physica B. 329-333。

H.Nojiri, T.Taniguchi, Y.Ajiro, A.M.Muller, B.Barbara: "Quantum dynamics of molecular magnets in ultra-fast sweeping magnetic Fields"Physica B. 346-347. 216-220 (2004)

H.Nojiri、T.Taniguchi、Y.Ajiro、A.M.Muller、B.Barbara：“超快扫描磁场中分子磁体的量子动力学”Physica B. 346-347。

H.Hachisuka, K.Awaga, T.Yokoyama, T.Kubo, T.Goto, H.Nojiri: "Structure and magnetic properties of single-molecule magnet Mn_<11>Cr : Magneization manipulation and internal field in the mixed crystals of Mn_<11>Cr and"Physical Review B. (in print). (2004)

H.Hachisuka、K.Awaga、T.Yokoyama、T.Kubo、T.Goto、H.Nojiri：“单分子磁体 Mn_<11>Cr 的结构和磁性：混合晶体中的磁化操纵和内场

T.Asano, H.Nojiri, Y.Inagaki, T.Sakon, J-P.: "ESR study of sine-Gordon excitations in S=1/2 antiferromagnet chain : copper benzoate"Physica B. 329-333. 1213-1214 (2003)

T.Asano、H.Nojiri、Y.Inagaki、T.Sakon、J-P.：“S=1/2 反铁磁体链中正弦戈登激发的 ESR 研究：苯甲酸铜”Physica B. 329-333。