New Development of Mossbauer Spectroscopy

穆斯堡尔谱学是在大约40年前发现的，已经成为固体物理领域的有力工具之一。本项目的目标是在穆斯堡尔谱学方面取得新的发展和成果，为材料科学，如纳米级的细粒子科学，也为鳗系元素科学做出贡献。我们在以下研究项目中发展了穆斯堡尔谱学。特别要强调的是，同步辐射核共振散射的最新发展和应用对于这一光谱在材料科学中的进一步发展是非常重要和必不可少的。氢氧化铁的穆斯堡尔谱研究暴露在自然环境中的钢表面上形成的腐蚀产物由α-FeOOH针铁矿、β-FeOOH Akagneit和γ-FeOOH鳞锌矿等氧氢氧化物组成。我们对这些羟基氧化物进行了穆斯堡尔谱测量，并测定了这些化合物…的相对量更多的是S对于钢材表面的锈迹。这些成果被报道并发表在国际会议上。纳米微粒的穆斯堡尔谱研究用穆斯堡尔谱对包硼的Fe微粒和SiO_2包覆的FePT微粒进行了穆斯堡尔谱测量。结果表明，包覆B的Fe为完整的bcc-Fe相，退火后的FePt细小颗粒为四方相L10-FePt有序合金，具有四方结构。用外差方法成功地观测到了新近发展起来的同步辐射核共振散射和同步辐射核共振散射。使用安装在SPring8上的相同装置，我们成功地首次观测到旋转楔形Lucite盘对^&lt；181&tt；Ta核共振光子的相位调制。通过同步辐射的核共振散射的观测，为高能区的相位调制和频率调制等超高分辨率光学的研究开辟了新的领域。穆斯堡尔谱在鳗系元素科学中的应用~(237)Np和~(238)U是非常重要的鳗系元素。近年来，在NpFeGa_5等元素化合物中发现了新的磁性和超导电性。在东北大学和日本原子能研究机构的合作下，对NpFeGa_5进行了穆斯堡尔谱测量，并详细讨论了它的磁性，并发表在国际会议上。较少

Mossbauer spectroscopy was discovered about 40 years ago and has been used as one of the powerful tools in the field of solid-state physics. This project aims to get new developments and achievements in this Mossbauer spectroscopy and to contribute in material science like the nanometer-sized fine particle science and also for the actinide science. We have developed Mossbauer spectroscopy in the following research projects. Especially, we have to emphasize that the recent development and application of the nuclear resonant scattering with synchrotron radiation is quite important and essential for the further progress of this spectroscopy in material science.1. Mossbauer spectroscopic study of iron oxyhydroxidesCorrosion products formed on steel surfaces exposed to nature environment consist of oxyhydroxides like α-FeOOH Goethite, β-FeOOH Akaganeit and γ-FeOOH Lepidocrocite. We performed Mossbauer measurements for these oxyhydroxides and determined relative quantities for these compound … More s for the rust on the steel surface. These results obtained was reported and published in international conference.2. Mossbauer spectroscopic study of nano-meter-sized fine particlesMossbauer measurements have been performed for the boron-coated Fe fine particles and SiO_2 coated FePt fine particles. Results obtained clearly show that the B-coated Fe is perfect bcc-Fe and annealed FePt fine particles are tetragonal L1_0 FePt ordered alloy having tetragonal structure.3. Newly developed nuclear resonant scattering with synchrotron radiation^<181>Ta nuclear resonant scattering with synchrotron radiation was successfully observed using heterodyne method in SPring8. Using a same facility installed in SPring8,we have succeeded a first observation of the phase modulation of ^<181>Ta nuclear resonant photons by a rotating wedge shaped Lucite disk. This observation by the nuclear resonant scattering with synchrotron radiation make it possible to open the new field of the ultra-high resolution optics like phase and frequency modulations in high energy region.4. Application of the Mossbauer spectroscopy to the actinide science^<237>Np and ^<238>U are very important actinide elements. Recently novel magnetism and superconductivity have been discovered in some actinide compounds, like NpFeGa_5. Under the collaboration with Tohoku University and Japan Atomic Research Agency, ^<57>Fe Mossbauer measurements have been performed for NpFeGa_5 and discussed its magnetic propertied in detail and published in International conference. Less