Resolving the spin reorientation and crystal-field transitions in TmFeO3 with terahertz transient

Abstract

Rare earth orthoferrites (RFeO3) exhibit abundant physical properties such as, weak macroscopic magnetization, spin reorientation transition, and magneto-optical effect, especially the terahertz magnetic response, have received lots of attention in recent years. In this work, quasi-ferromagnetic (FM) and quasi-antiferromagnetic (AFM) modes arising from Fe sublattice of TmFeO3 single crystal are characterized in a temperature range from 40 to 300 K, by using terahertz time-domain spectroscopy (THz-TDS). The magnetic anisotropy constants in ac-plane are estimated according to the temperature-dependent resonant frequencies of both FM and AFM modes. Here, we further observe the broad-band absorptions centered ~0.52, ~0.61, and ~1.15 THz below 110 K, which are reasonably assigned to a series of crystal-field transitions (R modes) of ground multiplets (6H3) of Tm3+ ions. Specially, our finding reveals that the spin reorientation transition at a temperature interval from 93 to 85 K is driven by magnetic anisotropy, however, which plays negligible role on the electronic transitions of Tm ions in the absence of applied magnetic fields.

Very weak bonds to artificial atoms formed by quantum corrals

“…In the case of crystal-field-split ground-state transitions of TmFeO 3 in the temperature interval between 80 K and 90 K, where the imaginary part of the dielectric function ε 2 is much smaller than its real part ε 1 (see ref. 31 ), the effective conductivity can be approximated by σ ε α = n c 0 sub eff . Here n sub = 4.92 is the refractive index of TmFeO 3 , and α eff ≈ 4,000 m −1 is the effective THz absorption coefficient obtained from data of ref.…”

“…Here n sub = 4.92 is the refractive index of TmFeO 3 , and α eff ≈ 4,000 m −1 is the effective THz absorption coefficient obtained from data of ref. 31 , taking into account the spectral shape of our THz pulse. We obtain…”

Dynamic Terahertz Plasmonics Enabled by Phase‐Change Materials

“…Many other materials showing dynamic THz responses applicable to active THz modulation also exist, such as NbO 2 , [211] InSb, [212,213] QWs, [214] titanium oxides, [215] orthoferrites, [216][217][218] rare-earth nickelates, [219][220][221] manganites, [222][223][224] topological insulators, [225][226][227] multiferroics, [228] molecular crystals, [229,230] medicines, [231] polymers, [232][233][234][235][236][237][238] and halide perovskites, [239][240][241][242][243][244][245][246] to name but a few. Considering the diversity of the material properties and the control mechanisms, plasmonic hybridization may bring about new possibilities for a wide variety of active THz devices.…”

Terahertz Electrodynamics in Transition Metal Oxides

“…[131,[198][199][200][201][202][203][204][205][206][207][208][209][210][211][212] Figure 23 shows the THz power absorption spectra across the spin-reorientation transition in Dy 0.7 Er 0.3 FeO 3 single crystals by Suemoto et al [207] A quasi-ferromagnetic mode (F-mode at 0.25 THz) corresponding to precession of macroscopic magnetization was excited by the THz magnetic component at high temperature. The antiferromagnetic phase in RFeO 3 has three symmetry constrained magnetic configurations Γ 1 , Γ 2 , and Γ 4 for Fe 3+ -Fe 3+ coupling.…”