X-ray Spectroscopy at Ultra-High Pressure: Present and Future
作者单位：Laboratoire de Mineralogie-CristallographieCNRS4 place Jussieu75252 Paris cedex 05France Laboratoire de Mineralogie-CristallographieCNRS4 place Jussieu75252 Paris cedex 05France Laboratoire de Mineralogie-CristallographieCNRS4 place Jussieu75252 Paris cedex 05France ESRF BP 220GrenobleFrance ESRF BP 220GrenobleFrance ESRF BP 220GrenobleFrance ESRF BP 220GrenobleFrance ESRF BP 220GrenobleFrance CEA-DAM Bruyeres-le-ChatelFrance arnegie InstitutionWashington DCUSA arnegie InstitutionWashington DCUSA
会议名称：《18th International Conference on High Pressure Science and Technology》
会议日期：2001年
学科分类：081704[工学-应用化学] 07[理学] 08[工学] 0817[工学-化学工程与技术] 070302[理学-分析化学] 0703[理学-化学]
关 键 词：High Pressure X-ray Spectroscopy Phonons Electronic Structure Magnetism
摘 要：正High pressure research has entered the era of high-end state of the art measurements, especially in the field of synchrotron x-ray research. Nowadays, a large number of techniques are readily available and applicable in conjunction with the most widely used high pressure apparatus, namely the diamond anvil cell. In the past years, diffraction constituted the largest part of high-pressure synchrotron-based x-ray research, along with limited efforts in the field of x-ray absorption spectroscopy. The appearance of high-energy third generation x-ray sources （ESRF, APS, SPring-8） allowed extremely brilliant x-ray beams to be focused down to very small sizes, due to the conjunction of high flux, small source size and divergence, and high coherence. With the help of an x-ray spectrometer set up in the Rowland geometry （figure 1） and low-Z （x-ray transparent） gaskets, a wide variety of high-resolution spectroscopic techniques can be accessed. We will briefly present techniques such as high resolution x-ray emission as local probe for magnetism and electronic modifications, as well as resonant x-ray scattering （x-ray Raman）. Inelastic x-ray scattering with ultra-high resolution allows us to access the vibrational properties （acoustic and optical phonons） of materials. These new techniques allowed us to investigate the electronic and magnetic properties of wiistite （FeO）, hematite （Fe2O3） and iron （Fe） well into the megabar pressure range. FeO is shown to become a paramagnetic compound at high pressure, and a closed-loop anti-ferromagnetic stability domain is depicted [1]. The vibrational properties （longitudinal and transverse sound wave velocities, and optical phonons in some cases） of iron （Fe） [2] and iron-bearing compounds （FeSi, FeS, FeS2, and FeO） [3-4] were measured to megabar pressures by ultra-high resolution （4 meV） inelastic x-ray scattering, along with the acoustic phonon dispersion curves. This set of data provides the first d