Berlin 2008 – scientific programme
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MA: Fachverband Magnetismus
MA 18: Poster I : Bio Magn. (1-2); Mag.Imgaging (3-9); Magn. Semiconductors (10-16); Half Metals & Oxides (17-20); Coupl.Phenomena (21-27); Magn. Mat. (28-41); Micro & Nanostr. Magn. Materials (42-61); Micro Magn. (62-64); Surface Magnetism (65-70); Transport Phenomena (71-85)
MA 18.36: Poster
Tuesday, February 26, 2008, 15:15–18:30, Poster E
Raman study of FeSi under high pressures up to 15 GPa — •Ivan Jursic, Ana Maria Racu, Dirk Menzel, and Joachim Schoenes — Institut für Physik der Kondensierten Materie, TU Braunschweig, Mendelsohnstr. 3, 38106 Braunschweig, Germany
Single crystals of FeSi which were grown by the Czochralski technique have been investigated by Raman spectroscopy up to pressures of 15 GPa. The measurements were performed at room temperature in a diamond anvil cell (DAC) using Daphne7373 oil as a pressure transmitting medium.
FeSi crystallizes in the B20 structure for which the factor group analysis predicts 9 Raman active modes. Measurements on larger crystals outside of the DAC allowed the assignment of all vibrations.[1] In the DAC only the stronger E-mode vibrations at 182 cm−1 and 313 cm−1 and the T-mode vibration at 310 cm−1 could be observed.
With increasing pressure the frequencies of the vibrations shift to higher wave numbers. For all the observed modes the Grüneisen parameters are calculated and compared to the values from temperature dependent measurements at ambient pressure. The data are discussed in terms of both localized and itinerant models of FeSi.
[1]A.-M. Racu et. al., Phys. Rev. B 76, 115103(2007)