Low Temperature Physics: 33, 915 (2007); https://doi.org/10.1063/1.2747049 (5 pages)
Fizika Nizkikh Temperatur: Volume 33, Number 11 (November 2007), p. 1206-1212 ( to contents , go back )
Raman Light Scattering by low-energy electronic excitations of ion Tb3+ in KTb(WO4)2 crystal
V.V. Eremenko, V.S. Kurnosov, A.V. Peschanskii, V.I. Fomin, and E.N. Khatsko
B. Verkin Institute for Low Temperature Physics and Engineering of the National Academy of Sciences of Ukraine 47 Lenin Ave., Kharkov 61103, Ukraine
Received February 19, 2007, revised April 18, 2007
The Raman scattering spectrum of a KTb(WO4)2 single crystal is investigated in a frequency range 3–950 cm–1 at temperatures 5, 80, and 300 K and their symmetry is determined. All 36 vibrational modes predicted by the group theory analysis are detected. The temperature dependence of the scattering spectra suggests that there is no phase transition in the above temperature range. It is found that there are low-energy electron transitions between the levels of main multiplet 7F6 of ion Tb3+ split by the crystal field of symmetry C2. The first excited electron quasi-doublet consists of two singlet levels of different symmetry, and it is separated from the main quasi-doublet by rather high energy (~ 75 cm–1). The behavior of all detected levels is investigated in external magnetic fields H ^ С2 and H || С2. The experimetal results support the view that at low temperatures the case of pure Ising anisotropy is realized, and that the underconsideration magnet may be regarded as a system of two-level magnetic ions.
PACS: 71.70.Ch Crystal and ligands fields;
Key words: low-energy electronic excitation, phonon.