Mikrofokussierendes Röntgendiffraktometer
Zusammenfassung der Projektergebnisse
The diffractometer has been mainly used for characterization of materials resulting from high-pressure and high-temperature syntheses. For many studies it is very important to be able to characterize the synthesized samples, in terms of phases present in the synthesis runs, before any further analysis which often requires crashing and grinding the material. The high versatility of the sample holder allows samples having different sizes and shapes to be measured. The 50 µm X-ray beam is particularly suited for analyzing very small samples. Moreover the high brilliance of the microfocus source together with the very sensitive detector allows obtaining diffraction patterns of these small samples in few hours. The resolution obtained is such that up to 4 – 5 phases having low symmetry space groups can be resolved if their structure is known. The diffractometer also is currently being tested for texture analysis, since it has been built with the possibility of collecting rocking curves. The followings are representative research achievement obtained by using the current apparatus. 1) A pressure exceeding 65 GPa was generated by a multi-anvil press with carbide anvils for the first time in the world. A simultaneous generation of pressure of 45 GPa and temperature of 2000 K was also achieved. 2) A high pressure phase of pyrope with the LiNbO3 structure was first synthesized, and its structure was determined by powder X-ray diffraction. 3) Stability of Fe4O5, Fe5O6 and Fe4O5-rich solid solutions was determined. 4) Large wadsleyite crystals were synthesized without flux.
Projektbezogene Publikationen (Auswahl)
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(2015): Synthesis of large wadsleyite single crystals by solidstate recrystallization, Amer Mineral 100, 2336-2339
Kawazoe, T.; Buchen, J.; Marquardt, H.
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(2016): Creep strength of ringwoodite measured at pressure-temperature conditions of the lower part of the mantle transition zone using a deformation-DIA apparatus. Earth Planet Sci Lett. 454, 10-19
Kawazoe, T.; Nishihara, Y.; Ohuchi, T.; Miyajima, N.; Maruyama, G.; Higo, Y.; Funakoshi, K.; Irifune, T.
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(2016): Generation of pressures over 40 GPa using Kawai-type multi-anvil press with tungsten carbide anvils. Review of Scientific Instruments 87, 024501
Ishii, T.; Shi, L.; Huang, R.; Tsujino, N.; Druzhbin, D.; Myhill, R.; Li, Y.; Wang, L.; Yamamoto, T.; Miyajima, N.; Kawazoe, T.; Nishiyama, N.; Higo, Y.; Tange, Y.; Katsura, T.
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(2016): New constraints on upper mantle creep mechanism inferred from silicon grain-boundary diffusion rates. Earth Planet Sci Lett. 433, 350-359
Fei, H.; Koizumi, S.; Sakamoto, N.; Hashiguchi, M.; Yurimoto, H.; Marquardt, K.; Miyajima, N.; Yamazaki, D.; Katsura, T.
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(2016): On the P-T fO2 stability of Fe4O5, Fe5O6 and Fe4O5-rich solid solutions. Contrib Mineral Petrol 171, 51
Myhill, R.; Ojwang, D.; Ziberna, L.; Frost, D.J.; Boffa Ballaran, T.; Miyajima, N.
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Coupled substitution of Fe3+ and H+ for Si in wadsleyite: a study by polarized infrared and Moessbauer spectroscopies and single-crystal X-ray diffraction, Amer. Mineral. 101, 1236-1239
Kawazoe, T.; Chaudhari, A.; Smyth, J.R.; Mccammon, C.
