Far-IR magnetospectroscopy of magnons and electromagnons in TbFeO3 single crystals at low temperatures
| Autor: | T. N. Stanislavchuk, S. W. Cheong, Andrei Sirenko, Yazhong Wang |
|---|---|
| Rok vydání: | 2017 |
| Předmět: |
Physics
Condensed matter physics Magnon Resonance 02 engineering and technology Atmospheric temperature range 021001 nanoscience & nanotechnology 01 natural sciences Magnetic field Polarization density 0103 physical sciences Antiferromagnetism 010306 general physics 0210 nano-technology Néel temperature Excitation |
| Zdroj: | Physical Review B. 95 |
| ISSN: | 2469-9969 2469-9950 |
| Popis: | Transmittance spectra of $\mathrm{TbFe}{\mathrm{O}}_{3}$ single crystals have been studied in the far-infrared spectral range $15\ensuremath{-}120\phantom{\rule{0.16em}{0ex}}\mathrm{c}{\mathrm{m}}^{\ensuremath{-}1}$ in the external magnetic fields up to 9 T and at low temperatures down to 1.5 K. The temperature and magnetic-field dependencies of the antiferromagnetic resonance (AFMR) modes have been measured below and above the magnetic ordering temperature of Tb moments ${T}_{N}^{\mathrm{Tb}}=3.3\phantom{\rule{0.28em}{0ex}}\mathrm{K}$. Both the quasiferromagnetic and quasiantiferromagnetic modes of AFMR demonstrate hardening at $Tl{T}_{N}^{\mathrm{Tb}}$. The quasiantiferromagnetic mode gains electric-dipole activity along the $c$ axis below ${T}_{N}^{\mathrm{Tb}}$ and thus behaves as a hybrid, i.e., both electric- and magnetic-dipole active, mode. In addition to AFMR modes, below ${T}_{N}^{\mathrm{Tb}}$ we observed the appearance of electromagnon excitation at about $27\phantom{\rule{0.16em}{0ex}}\mathrm{c}{\mathrm{m}}^{\ensuremath{-}1}$, which is electric-dipole active along the $c$ axis. The electromagnon is optically active only in a narrow temperature range, $2.7\phantom{\rule{0.16em}{0ex}}\mathrm{K}lTl{T}_{N}^{\mathrm{Tb}}$ at $H=0$, and in a narrow range of magnetic fields 2.4--2.7 T applied along the $b$ axis at $T=1.5\phantom{\rule{0.16em}{0ex}}\mathrm{K}$. We argue that this electromagnon appears in magnetic phases, which are compatible with a spontaneous electric polarization along the $b$ axis. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|