Parts | Days | Selection | Search | Updates | Downloads | Help
TT: Fachverband Tiefe Temperaturen
TT 44: Poster Session Correlated Electrons
TT 44.40: Poster
Thursday, March 17, 2011, 10:00–13:00, P1
Infrared properties of magnetite under pressure — •Jihaan Ebad-Allah1, Leonetta Baldassarre1, Michael Sing2, Ralph Claessen2, Vic Brabers3, and Christine Kuntscher1 — 1Experimentalphysik II, Universität Augsburg, D-86159 Augsburg, Germany — 2Experimentelle Physik 4, Universität Würzburg, D-97074 Würzburg, Germany — 3Department of Physics, Eindhoven University of Technology, 5600 MB Eindhoven, the Netherlands
Magnetite (Fe3O4) crystallizes in the inverse cubic spinel structure and undergoes a Verwey transition at Tv≈120 K at ambient pressure. By applying pressure, Tv decreases with increasing pressure according to the phase diagram proposed in [1]. In addition, it was recently suggested that at room temperature (RT) magnetite undergoes a pressure-induced phase transition from the inverse spinel to the normal spinel structure above 6 GPa, without a change in the lattice symmetry. This proposal is, however, controversially discussed [2].
We studied the electronic and vibrational properties of magnetite by
infrared reflectance measurements. First, in order to verify the
conduction mechanism via polaron hopping and to search for possible
signatures of the phase transition at around 6 GPa, we measured the
RT reflectance as a function of pressure. Secondly, we carried out
the low-temperature reflectance measurements under pressure in the
far-infrared range to check the effect of high pressure on Tv
and the splitting of the phonon modes.
G. Kh. Rozenberg et al., Phys. Rev. Lett. 96, 045705 (2006).
S. V Ovsyannikov et al., J. Phys.: Condens. Matter 20, 172201 (2008).