High-pressure phase transition of Bi2Fe4O9

作者：Friedrich Alexandra^*; Biehler Jasmin; Morgenroth Wolfgang; Wiehl Leonore; Winkler Bjoern; Hanfland Michael; Tolkiehn Martin; Burianek Manfred; Muehlberg Manfred

来源：Journal of Physics: Condensed Matter , 2012, 24(14): 145401.

DOI：10.1088/0953-8984/24/14/145401

The high-pressure behaviour of Bi2Fe4O9 was analysed by in situ powder and single-crystal x-ray diffraction and Raman spectroscopy. Pressures up to 34.3(8) GPa were generated using the diamond anvil cell technique. A reversible phase transition is observed at approximately 6.89(6) GPa and the high-pressure structure is stable up to 26.3(1) GPa. At higher pressures the onset of amorphization is observed. The crystal structures were refined from single-crystal data at ambient pressure and pressures of 4.49(2), 6.46(2), 7.26(2) and 9.4(1) GPa. The high-pressure structure is isotypic to the high-pressure structure of Bi2Ga4O9. The lower phase transition pressure of Bi2Fe4O9 with respect to that of Bi2Ga4O9 (16 GPa) confirms the previously proposed strong influence of cation substitution on the high-pressure stability and the misfit of Ga3+ and Fe3+ in tetrahedral coordination at high pressure. A fit of a second-order Birch-Murnaghan equation of state to the p-V data results in K-0 = 74.3/GPa for the low-pressure phase and K-0 = 79.2/GPa for the high-pressure phase. The mode Gruneisen parameters were obtained from Raman-spectroscopic measurements.

• 出版日期2012-4-11