title: 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 ((6)H3) of Tm(3+) 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.
authors.affiliation: Department of Physics, Shanghai University, Shanghai 200444, China.
authors.forename: Kailin
authors.initials: K
authors.lastname: Zhang
authors.affiliation: Department of Physics, Shanghai University, Shanghai 200444, China.
authors.forename: Kai
authors.initials: K
authors.lastname: Xu
authors.affiliation: Department of Physics, Shanghai University, Shanghai 200444, China.
authors.forename: Xiumei
authors.initials: X
authors.lastname: Liu
authors.affiliation: Department of Physics, Shanghai University, Shanghai 200444, China.
authors.forename: Zeyu
authors.initials: Z
authors.lastname: Zhang
authors.affiliation: Department of Physics, Shanghai University, Shanghai 200444, China.
authors.forename: Zuanming
authors.initials: Z
authors.lastname: Jin
authors.affiliation: Department of Physics, Shanghai University, Shanghai 200444, China.
authors.forename: Xian
authors.initials: X
authors.lastname: Lin
authors.affiliation: Key Laboratory of Polar Materials and Devices, East China Normal University, Shanghai 200241, China.
authors.forename: Bo
authors.initials: B
authors.lastname: Li
authors.affiliation: Department of Physics, Shanghai University, Shanghai 200444, China.
authors.forename: Shixun
authors.initials: S
authors.lastname: Cao
authors.affiliation: Department of Physics, Shanghai University, Shanghai 200444, China.
authors.forename: Guohong
authors.initials: G
authors.lastname: Ma