Spin and lattice excitations of a BiFeO3 thin film and ceramics

Abstract

We present a comprehensive study of polar and magnetic excitations in BiFeO3 ceramics and a thin film epitaxially grown on an orthorhombic (110) TbScO3 substrate. Infrared reflectivity spectroscopy was performed at temperatures from 5 to 900 K for the ceramics and below room temperature for the thin film. All 13 polar phonons allowed by the factor-group analysis were observed in theceramic samples. The thin-film spectra revealed 12 phonon modes only and an additional weak excitation, probably of spin origin. On heating towards the ferroelectric phase transition near 1100 K, some phonons soften, leading to an increase in the static permittivity. In the ceramics, terahertz transmission spectra show five low-energy magnetic excitations including two which were not previously known to be infrared active; at 5 K, their frequencies are 53 and 56 cm-1. Heating induces softening of all magnetic modes. At a temperature of 5 K, applying an external magnetic field of up to 7 T irreversibly alters the intensities of some of these modes. The frequencies of the observed spin excitations provide support for the recently developed complex model of magnetic interactions in BiFeO3 (R.S. Fishman, Phys. Rev. B 87, 224419 (2013)). The simultaneous infrared and Raman activity of the spin excitations is consistent with their assignment to electromagnons.

References in corpus (22)

• Colossal Spin-Phonon Anomalies and the Ferroelectric Phase Transition in the Model Multiferroic Bifeo3
• Electric-field control of spin waves at room temperature in multiferroic BiFeO3
• Infrared and THz studies of polar phonons and improper magnetodielectric effect in multiferroic BFO3 ceramics
• Observation of electromagnon excitations in the BiFe0${}_3$ spiral magnet
• Infrared phonon dynamics of multiferroic BiFeO3 single crystal
• Structure and spin dynamics of multiferroric BiFeO${}_3$
• Optical coupling to spin waves in the cycloidal multiferroic BiFeO3
• Spin wave measurements over the full Brillouin zone of multiferroic BiFeO3
• Polar phonons and spin excitations coupling in multiferroic BiFeO3 crystals
• Long wavelength magnetic and magnetoelectric excitations in the ferroelectric antiferromagnet BiFeO3
• Terahertz spectroscopy of spin waves in multiferroic BiFeO${}_3$ in high magnetic fields
• The Spin State and Spectroscopic Modes of Multiferroic BiFeO3
• Temperature-Dependent Interplay of Dzyaloshinskii-Moriya Interaction and Single-Ion Anisotropy in Multiferroic BiFeO${}_3$
• Model for twin electromagnons and magnetically induced oscillatory polarization in multiferroic RMnO${}_3$
• Phonon Spectroscopy Near Phase Transition Temperatures in Multferroic BiFeO3 Epitaxial Thin Films
• Anharmonic Phonons and Magnons in BiFeO3
• Field dependence of the Spin State and Spectroscopic Modes of Multiferroic BiFeO${}_3$
• Identifying the Magnetoelectric Modes of Multiferroic BiFeO${}_3$
• Magnetic susceptibility, phonons and dielectric constant of single crystalline BiFeO3
• Thermal evolution of the full three-dimensional magnetic excitations in the multiferroic BiFeO3
• High Temperature Emissivity, Reflectivity, and X-ray absorption of BiFeO3
• Sinusoidal electromagnon in RMnO3: Indication of anomalous magnetoelectric coupling

Cited by in corpus (8)

• Optical diode effect in the room-temperature multiferroic BiFeO$_3
• Far infrared and terahertz spectroscopy of ferroelectric soft modes in thin films: A review
• Ultrafast Light-driven Simultaneous Excitation of Coherent Terahertz Magnons and Phonons in Multiferroic BiFeO${}_3$
• Electromagnon in the Z-type hexaferrite $({\mathrm{Ba}}_x{\mathrm{Sr}}_{1-x}{)}_3\mathrm{C}{\mathrm{o}}_2\mathrm{F}{\mathrm{e}}_{24}{\mathrm{O}}_{41}$
• Electromagnon in Y-type hexaferrite BaSrCoZnFe${}_{11}$AlO${}_{22}$
• Structural investigation of (111) oriented (BiFeO3)(1-x)Λ/(LaFeO3)xΛ superlattices by X-ray diffraction and Raman spectroscopy
• Sub-millimeter propagation of antiferromagnetic magnons via magnon-photon coupling
• Observation of quasi-elastic light scattering in BiFeO${}_3$