Experimental and theoretical studies of vibrational density of states in Fe3O4 single-crystalline thin films

作     者：B. Handke A. Kozłowski K. Parliński J. Przewoźnik T. Ślęzak A. I. Chumakov L. Niesen Z. Kąkol J. Korecki 

作者机构：Institute of Catalysis & Surface Chemistry Polish Academy of Sciences Kraków Poland Faculty of Physics & Applied Computer Science AGH University of Science and Technology Kraków Poland The Henryk Niewodniczański Institute of Nuclear Physics Polish Academy of Sciences Kraków Poland European Synchrotron Radiation Facility P.B. 200 F-38043 Grenoble France Nuclear Solid State Physics Material Science Center University of Groningen Nijenborg 4 9747 AG Groningen The Netherlands 

出 版 物：《Physical Review B》 (Phys. Rev. B Condens. Matter Mater. Phys.)

年 卷 期：2005年第71卷第14期

页      面：144301-144301页

核心收录：

学科分类：0808[工学-电气工程] 0809[工学-电子科学与技术（可授工学、理学学位）] 07[理学] 0805[工学-材料科学与工程（可授工学、理学学位）] 0702[理学-物理学] 

摘      要：This paper presents experimental and theoretical studies of lattice vibrations in a single-crystalline Fe3O4(001) thin film. The investigations were carried out in order to see how the lattice dynamics changes at the Verwey transition. Vibrational densities of states (DOS) were obtained from nuclear inelastic scattering (NIS) of synchrotron radiation in the temperature range 25 to 296 K, while theoretical DOS were calculated ab initio within density functional theory. Experimental phonon density of states shows good agreement with calculated DOS, reproducing both the general features of main line groups as well as the groups’ structure. This is also in qualitative accord with heat capacity data, provided that experimental DOS is augmented with that calculated for oxygen atoms. We have observed a gradual change in the NIS raw data as well as the relevant DOS while lowering the temperature. In particular, the main peak in the energy region 15–25 meV shows increasing splitting on cooling. The Lamb-Mössbauer factor calculated in the course of DOS evaluation shows a pronounced drop in the vicinity of the Verwey transition that may be partly connected to the observed abrupt lowering of the count rate at approximately 7 meV for TTV. Since this is an indication of lattice stiffening below TV, we conclude that we have found experimental evidence for lattice participation in the mechanism leading to the Verwey transition.