Infrared and Raman studies of the Verwey transition in magnetite
We present infrared and Raman measurements of magnetite (Fe3O4). This material is known to undergo a metal-insulator and a structural transition (Verwey transition) at T-V = 120 K. The structural aspect of the Verwey transition is disclosed by the appearance of additional infrared-active and Raman-active phonons. The frequencies of the infrared-active phonons show no significant singularities at the transition whereas their linewidths increase. The frequency and linewidth of the Raman-active phonon at 670 cm(-1) change abruptly at the transition. For T<T-V, we observe fine structure in the infrared and Raman spectra which may indicate strong anharmonicity of the system below the transition. The effective mass of the mobile carriers is estimated to be m*approximate to 100m, where m is the electronic mass.
Univ Florida, Dept Phys, Gainesville, FL 32611 USA. NIST, Opt Technol Div, Gaithersburg, MD 20899 USA. Univ Maryland, Dept Phys, College Pk, MD 20742 USA. Ecole Polytech Fed Lausanne, Inst Phys Appl, Dept Phys, CH-1015 Lausanne, Switzerland. Ecole Polytech Fed Lausanne, IGA, Dept Phys, CH-1015 Lausanne, Switzerland. Gasparov, LV, Univ Florida, Dept Phys, POB 118440, Gainesville, FL 32611 USA.
ISI Document Delivery No.: 359CF
Record created on 2006-10-03, modified on 2016-08-08