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-AlOOH and investigation of symmetrization of hydrogen bondSano, Asami; Hattori, Takanori
no journal, ,
To investigate the relation between the symmetrization of hydrogen bond and change of physical properties in the hydrous mineral of the -AlOOH, we conducted neutron diffraction experiments at the high-pressure neutron diffractometer PLANET in the J-PARC. We observed the disappearance of 021 reflection at high pressure in -AlOOH which indicates the transition from the structure with asymmetric hydrogen bond (
) to that with disordered or symmetric hydrogen bond (
), in agreement with previous single crystal X-ray diffraction study. On the other hand the transition pressure is higher in -AlOOD, which was determined to be 12 GPa. The detail about the hydrogen distribution around the transition pressure and its relevance to the change of compressibility and anomalies in sound velocities will be discussed.
Tateiwa, Naoyuki
no journal, ,
Magnetic measurement at high pressure is an important experimental method for the study of magnetic properties of materials. Recently, we have developed a miniature ceramic-anvil high-pressure cell mCAC for magnetic measurements at pressures above 10 GPa in a commercial superconducting quantum interference (SQUID) magnetometer. In this conference, we will present basic performance of the mCAC and show interesting physical phenomena in some rare earth and actinide compounds: pressure-induced ferromagnetism in YbCu
Si and pressure-induced ferromagnetic to nonmagnetic transition in uranium ferromagnetic superconductor UGe.
Hattori, Takanori; Sano, Asami; Arima, Hiroshi*; Komatsu, Kazuki*; Funakoshi, Kenichi*; Abe, Jun*; Machida, Shinichi*; Ouchi, Keiichi*; Okazaki, Nobuo*
no journal, ,
PLANET is a high-pressure neutron beamline recently constructed at MLF in J-PARC. Most characteristic feature of the beamline is to possess the large six-axis multi-anvil high-pressure ATSUHIME press, which enables in-situ neutron diffraction under high pressure and high temperature condition up to 10 GPa and 2000 K. Smaller presses, a Paris-Edinburgh press and Mito cell, are also available and the accessible PT conditions with each device are 20 GPa at room temperature and 5 GPa at 77 K, respectively. The beamline is equipped with incident slits and receiving collimators that eliminates parasitic scattering from the high-pressure cell assembly to obtain clean data. The high performance of the diffractometer and low-parasitic scattering characteristics enables precise structure determination of crystals and liquids under high pressure and temperature conditions. In this presentation, the specification of the PLANET and recent results obtained at PLANET are introduced.