Spin-selective XAFS: a noble analytical method for magnetic nano-particles

自旋选择性 XAFS：一种出色的磁性纳米颗粒分析方法

• 批准号: 17510094
• 负责人: HAYASHI Hisashi
• 金额: $ 2.3万
• 依托单位: Japan Women's University (2006)Tohoku University (2005)
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2005
• 资助国家: 日本
• 起止时间: 2005 至 2006
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-17510094/
• 关键词: Spin-selective XAFS; Resonant inelastic x-ray scattering; X-ray spectrometer with high-sensitivity; X-ray satellites; Magnetic nano-particles

This project aims to establish spin-selective XAFS spectroscopy as a method of characterizing the magnetic and electronic structure of magnetic nano-particles. Here it is necessary to develop high-resolution x-ray spectrometers with large acceptance in order to measure generally weak Kβ-emissions of 3d elements.In 2005, our own dispersive-type spectrometer was modified for detecting Kβ-emissions, and was utilized for observing resonant inelastic x-ray scattering (RIXS) of several standard materials to deduce their spin-selective XAFS. Through these measurements, it has been achieved to ultimately suppress lifetime-broadenings, and to obtain polarized spin-selective XAFS for single-crystal of LaMnO_3. On the other hand, it has been found that magnetic nano-particles are unstable for incident x-rays produced by synchrotron sources. The instability made it difficult to precisely obtain the spin-selective XAFS of the particles.Thus, in 2006, a focusing-type spectrometer was made by rebuilding the dispersive-type spectrometer, and was named as 'Peacock' after its shape. By using the 'Peacock', lifetime-broadening-suppressed XAFS spectra of CuO nano-particles on ZnO with various Cu concentrations up to as low as 1 mol% were obtained from their RIXS. Similar experiments for a basic high-Tc system, La_<2-x>Sr_xCuO_4 (LSCO) reveal that 1s-3d excitation of LSCO is very sensitive Sr-concentration and polarization. After these preliminary studies to demonstrate the high-sensitivity of 'Peacock', spin-selective XAFS spectra of magnetic nano-materials of several Fe oxides were measured within fairly short periods. Here almost no radiation-damage was distinguishable. Based on the data obtained, papers are now in preparation.

本项目旨在建立自旋选择性XAFS光谱作为表征磁性纳米粒子的磁性和电子结构的方法。为了测量三维元素普遍较弱的k β-发射，有必要研制高分辨率、高接受度的x射线光谱仪。2005年，我们对自己的色散型光谱仪进行了改进，用于探测k β发射，并用于观察几种标准材料的共振非弹性x射线散射（RIXS），以推断其自旋选择性XAFS。通过这些测量，最终实现了抑制寿命加宽，并获得了LaMnO_3单晶的极化自旋选择性XAFS。另一方面，已经发现磁性纳米粒子对同步加速器源产生的入射x射线不稳定。这种不稳定性使得精确获得粒子的自旋选择性XAFS变得困难。于是，在2006年，对色散型光谱仪进行了改造，制成了聚焦型光谱仪，并以其外形命名为“孔雀”。利用“Peacock”光谱，获得了Cu浓度低至1 mol%的氧化锌上CuO纳米粒子的寿命展宽抑制XAFS光谱。对La_<2-x>Sr_xCuO_4 （LSCO）基本高tc体系的类似实验表明，LSCO的1s-3d激发对sr浓度和极化非常敏感。在这些初步研究证明了“孔雀”的高灵敏度之后，在相当短的时间内测量了几种铁氧化物的磁性纳米材料的自旋选择性XAFS光谱。这里几乎没有明显的辐射损伤。根据获得的数据，论文正在准备中。

项目成果

Selective XANES spectroscopy from RIXS contour maps

RIXS 等高线图的选择性 XANES 光谱

• 发表时间: 2005
• 期刊: J. Phys. Chem. Solids 66
• 作者: E.Jalbista;N.Ohta;Hisashi Hayashi
• 通讯作者: Hisashi Hayashi

Observation of fine structure in quadrupolar transition of Ho L3 pre-edge by lifetime-broadening-suppressed XANES spectroscopy

通过抑制寿命展宽的 XANES 光谱观察 Ho L3 前边缘四极转变的精细结构

• 发表时间: 2005
• 期刊: Phys. Rev. B 72
• 作者: Y.Udagawa;H.Hayashi;A.Sugiyama et al.;H.Hayashi et al.;H.Hayashi et al.;H.Hayashi et al.;H.Hayashi et al.;H.Hayashi et al.;H.Hayashi et al.;H.Hayashi et al.;H.Hayashi et al.;H.Hayashi et al.
• 通讯作者: H.Hayashi et al.

内殻分光(うち6.5章を分担執筆)

内壳光谱学（合着6.5章）

• 发表时间: 2007
• 作者: 宇田川 康夫;林 久史
• 通讯作者: 林 久史

Spin-polarized Man K-edge XANES analysis of Mn oxides

锰氧化物的自旋极化 Man K 边 XANES 分析

• 发表时间: 2007
• 期刊: J. Magn. Mag. Mat. 310
• 作者: Y.Udagawa;H.Hayashi;A.Sugiyama et al.
• 通讯作者: A.Sugiyama et al.

Polarized lifetime-broadening-suppressed XANES study of La_<2-x>MS_xCuO_4

La_<2-x>MS_xCuO_4 的偏振寿命展宽抑制 XANES 研究

• 发表时间: 2006
• 期刊: Rad. Phys. Chem 75(11)
• 作者: Y.Udagawa;H.Hayashi;A.Sugiyama et al.;H.Hayashi et al.;H.Hayashi et al.
• 通讯作者: H.Hayashi et al.