caa a22 4500 463217195 CHVBK 20180405153200.0 cr unu---uuuuu 170326e20071101xx s 000 0 eng 10.1007/s00269-007-0177-3 doi (NATIONALLICENCE)springer-10.1007/s00269-007-0177-3 Effect of non-hydrostatic conditions on the elastic behaviour of magnetite: an in situ single-crystal X-ray diffraction study [Elektronische Daten] [G. Gatta, I. Kantor, T. Boffa Ballaran, L. Dubrovinsky, C. McCammon] The high-pressure elastic behaviour and the pressure-induced structural evolution of synthetic magnetite were investigated up to 11.11(5)GPa by means of in situ single-crystal X-ray diffraction with a diamond anvil cell, using the mix methanol:ethanol:water=16:3:1 as pressure-transmitting medium and the ruby-fluorescence method for pressure-calibration. The evolution of the ruby R1-fluorescence line with P, with a drastic increase of the full-width-at-half-maximum (FWHM) of the Lorentzian profile at P>9GPa, shows that the P-medium is not hydrostatic above 9GPa. Such a condition is well reflected by the drastic increase (by 20-22%) of the FWHM of the diffraction peak profiles of magnetite, by the behaviour of the Eulerian finite strain versus normalized pressures plot (f e -F e plot) and by the slight EoS-misfit. However, the diffraction data collected during decompression showed a reversible/complete restoration of the diffraction profiles and of the elastic behaviour in the f e -F e plot. The reflection conditions dictated by the $$ Fd\bar 3m $$ space group confirm that symmetry of magnetite is maintained within the P-range investigated. The structural refinements performed at 0.0001, 4.99(3) and 9.21(8)GPa show that the evolution of the oxygen u-parameter is almost constant within the P-range investigated. A weighted linear regression through the data points gives only a slight negative slope and no discontinuity is observed within the P-range investigated. A similar continuous behaviour is also observed in the evolution of the T- and M-polyhedral volumes, bond distances and angles with P. On the basis of data reported in this study, it appears that the elastic behaviour and the structural evolution of magnetite is drastically influenced by the experimental conditions (i.e., hydrostatic or non-hydrostatic), and diffraction data of magnetite collected under non-hydrostatic conditions are unusable for a reliable description of the elastic behaviour and for the P-induced structural rearrangements. Comparisons are carried out between the experimental findings of this study and those reported in the previous ones, in which an inverse-to-direct spinel phase transition at P>8GPa is suggested. Springer-Verlag, 2007 Magnetite nationallicence High-pressure nationallicence Elastic behaviour nationallicence Compressibility nationallicence Structural evolution nationallicence Gatta G. Dipartimento di Scienze della Terra, Università degli Studi di Milano, Via Botticelli, 23, 20133, Milan, Italy aut Kantor I. Bayerisches Geoinstitut, Universität Bayreuth, Bayreuth, Germany aut Boffa Ballaran T. Bayerisches Geoinstitut, Universität Bayreuth, Bayreuth, Germany aut Dubrovinsky L. Bayerisches Geoinstitut, Universität Bayreuth, Bayreuth, Germany aut McCammon C. Bayerisches Geoinstitut, Universität Bayreuth, Bayreuth, Germany aut Physics and Chemistry of Minerals Springer-Verlag 34/9(2007-11-01), 627-635 0342-1791 34:9<627 2007 34 269 https://doi.org/10.1007/s00269-007-0177-3 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s00269-007-0177-3 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Gatta G. Dipartimento di Scienze della Terra, Università degli Studi di Milano, Via Botticelli, 23, 20133, Milan, Italy aut NATIONALLICENCE 700 1- Kantor I. Bayerisches Geoinstitut, Universität Bayreuth, Bayreuth, Germany aut NATIONALLICENCE 700 1- Boffa Ballaran T. Bayerisches Geoinstitut, Universität Bayreuth, Bayreuth, Germany aut NATIONALLICENCE 700 1- Dubrovinsky L. Bayerisches Geoinstitut, Universität Bayreuth, Bayreuth, Germany aut NATIONALLICENCE 700 1- McCammon C. Bayerisches Geoinstitut, Universität Bayreuth, Bayreuth, Germany aut NATIONALLICENCE 773 0- Physics and Chemistry of Minerals Springer-Verlag 34/9(2007-11-01), 627-635 0342-1791 34:9<627 2007 34 269 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer