Terahertz emission spectroscopy of laser-induced spin dynamics inTmFeO3andErFeO3orthoferrites

Abstract

Using the examples of laser-induced spin-reorientation phase transitions in TmFeO 3 and ErFeO 3 orthoferrites, we demonstrate that terahertz emission spectroscopy can obtain novel information about ultrafast laser-induced spin dynamics, which is not accessible by more common all-optical methods. The power of the method is evidenced by the fact that, in addition to the expected quasi-ferromagnetic and quasi-antiferromagnetic modes of the iron sublattices, terahertz emission spectroscopy enables detection of a resonance optically excited at an unexpected frequency of ß0.3-0.35 THz. By recording how the amplitude and phase of the excited oscillations depend on temperature and applied magnetic field, we show that the unexpected mode has all the features of a spin resonance of the Fe 3+ ions. We suggest that it can be assigned to transitions between the multiplet sublevels of the 6 A 1 ground state of the Fe +3 ions occupying rare-earth positions.

Selective Excitation of Terahertz Magnetic and Electric Dipoles in Er3+ Ions by Femtosecond Laser Pulses in ErFeO3Mikhaylovskiy1, Huisman2, Pisarev3 et al. 2017Phys. Rev. Lett.Self Cite370260View full textAdd to dashboardCite

“…The complex emission spectrum consists of several narrow bands. Some of them with frequencies below 1 THz correspond to the magnetic resonances of the Fe 3þ sublattices as it was reported earlier [25,28]. Here we focus on the spectral components lying above 1 THz [ Fig.…”

“…Note that the helicity-dependent and helicity-independent THz waves change their polarizations by 90°in the temperature interval ∼50-70 K (see also the Supplemental Material [29], Fig. S4), which corresponds to the spin reorientation as was determined from the behavior of the spin resonances of the Fe 3þ sublattices [28]. For example, in the y-cut sample the helicity-dependent emission below 50 K has an electric field polarized along the x axis [ Fig.…”

“…However the frequencies of these components are slightly, but noticeably shifted with respect to the helicity-dependent bands. The polarization-independent emission can be divided into the main component polarized along the z axis in the Γ 2 phase and along the x axis in the Indeed, the polarization-independent mechanism of ultrafast excitation of the magnetic-dipole longitudinal-like magnetic modes of Fe 3þ ions has been recently demonstrated in orthoferrites [25,28].…”

Terahertz Emission Functionality of High‐Temperature Superconductors and Similar Complex Systems

“…Optical Mater. [129] Overall, it was shown that the THz emission spectroscopy has become a powerful tool and a viable option to optical pump-probe spectroscopy for studying magnetic materials. In magnetic systems, it is the magnetic permeability and its dynamics, which are key to THz emission.…”

“…2020, 8,1900892 mentation of THz emission spectroscopy to 2D systems is a viable and credible approach to realizing such ultrafast optical control. [128][129][130][131][132][133][134][135][136][137][138][139][140][141] In the specific area of active metamaterials research, combining the electronic and magnetic control with the optical THz functionality of metamaterials promises several new possibilities for the technological utility of THz light-matter interaction. [136,137] Thus, material research by and for THz technology is one of the most exciting research fields where we can study the intrinsic nature of materials and devices.…”