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Y. Yoshimura

Bio: Y. Yoshimura is an academic researcher. The author has contributed to research in topics: Diffraction & Phase transition. The author has an hindex of 2, co-authored 2 publications receiving 29 citations.

Papers
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Journal ArticleDOI
TL;DR: In this paper, a simple and versatile method of high-temperature stability is presented for x-ray diffraction measurements near room temperature, which is capable of being directly and easily mounted on the commercially available goniometer head.
Abstract: A simple and versatile method of high-temperature stability is presented for x-ray diffraction measurements near room temperature. The small sample cell for the measurements possesses coaxial multishells to guarantee the temperature homogeneity in the shells. It is capable of being directly and easily mounted on the commercially available goniometer head. A double-stage temperature control is adopted using both a heater and a thermoelectric module. The temperature is regulated by an optimized proportional integral derivative (PID) control. The base-line stability of the temperature at the sample stage in the cell is within ±0.5 mK. X-ray precession patterns of PbCsCl3 single crystal were taken at two temperatures separated by 30 mK across the phase transition point, showing the appearance and disappearance of a diffraction spot from the superstructure.

17 citations

Journal ArticleDOI
TL;DR: In this paper, a millikelvin (mK)-stabilized cell was developed for the detailed x-ray diffraction study of solid phase transitions, which is easily mounted on a commercially available goniometer head.
Abstract: Based on our technique of fine temperature control, we developed a new “millikelvin (mK)-stabilized cell” having a function of sensing thermal anomalies for the detailed x-ray diffraction study of solid phase transitions. It is easily mounted on a commercially available goniometer head. The performance was tested using CsPbCl3 single crystal, in which a phase transition is known to take place at 320 K (47°C) from tetragonal to cubic. An abrupt variation in the distance between some two reciprocal points in the precession pattern was clearly detected in a 0.1 K temperature range centered at 47°C along with two thermal anomalies observed. The “mK-stabilized cell” will be very useful to investigate a mechanism of phase transitions occurring in a narrow temperature range.

12 citations


Cited by
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Journal ArticleDOI
TL;DR: In this paper, the use of thermoelectric modules as heat flux sensor and as a heat pump in a hand-made calorimeter enables the authors to measure thermal phenomena with high sensitivity and high thermal stability at very slow heating and cooling rates.
Abstract: We constructed an apparatus that enables us to simultaneously detect structural changes of molecules and the accompanying thermal phenomena by combining a commercially available Raman spectrometer and a hand-made calorimeter. The use of thermoelectric modules as a heat flux sensor and as a heat pump in our calorimeter enables us to measure thermal phenomena with high sensitivity and high thermal stability at very slow heating and cooling rates. Efficiency is important to treat a small amount of sample and also to make the experimental conditions nearly quasi-static by balancing the heating effect of laser beam irradiation. As a performance test, we measured a prototype ionic liquid (IL), 1-buthyl-3-methylimidazolium bromide ([bmim]Br), which has some characteristic thermal properties. It was confirmed that the melting links to the cooperative conformational change of the butyl group in the [bmim]+ ion.

29 citations

Journal ArticleDOI
TL;DR: In this paper, X-ray diffraction measurements using a precession camera have clarified that BaTiO3 single crystals have coherent hybrid structures with tetragonal and monoclinic lattices.

14 citations

Journal ArticleDOI
TL;DR: In this paper, a cold stage for Bragg-Brentano geometry X-ray powder diffraction is described for use in the temperature range from about 250 to 300 K. The stage is constructed in such a way that it may be removed from the diffractometer and pre-cooled to its base temperature before the sample is loaded.
Abstract: A cold stage for Bragg–Brentano geometry X-ray powder diffraction is described for use in the temperature range from about 250 to 300 K. The stage is constructed in such a way that it may be removed from the diffractometer and pre-cooled to its base temperature before the sample is loaded. After loading, thermoelectric cooling maintains the specimen at low temperature (ice free) whilst the body of the stage is allowed to return to room temperature prior to remounting on the diffractometer.

13 citations

Journal ArticleDOI
TL;DR: In this paper, thermal and X-ray diffraction measurements were carried out for the phase transition in CsPbCl 3 using ''mK-stabilized cells' with the temperature stability less than a few mK.

12 citations

Journal ArticleDOI
TL;DR: In this paper, a millikelvin (mK)-stabilized cell was developed for the detailed x-ray diffraction study of solid phase transitions, which is easily mounted on a commercially available goniometer head.
Abstract: Based on our technique of fine temperature control, we developed a new “millikelvin (mK)-stabilized cell” having a function of sensing thermal anomalies for the detailed x-ray diffraction study of solid phase transitions. It is easily mounted on a commercially available goniometer head. The performance was tested using CsPbCl3 single crystal, in which a phase transition is known to take place at 320 K (47°C) from tetragonal to cubic. An abrupt variation in the distance between some two reciprocal points in the precession pattern was clearly detected in a 0.1 K temperature range centered at 47°C along with two thermal anomalies observed. The “mK-stabilized cell” will be very useful to investigate a mechanism of phase transitions occurring in a narrow temperature range.

12 citations