Influence of magnetic ordering on electronic structure of Tb3+ ion in TbFe3(BO3)4 crystal

A. V. Malakhovskii; S. L. Gnatchenko; I. S. Kachur; V. G. Piryatinskaya; A. L. Sukhachev; V. L. Temerov

doi:10.1140/epjb/e2011-10806-x

2022 Impact factor 1.6

Condensed Matter and Complex Systems

Eur. Phys. J. B 80, 1-10 (2011)
https://doi.org/10.1140/epjb/e2011-10806-x

Influence of magnetic ordering on electronic structure of Tb³⁺ ion in TbFe₃(BO₃)₄ crystal

A. V. Malakhovskii¹^a, S. L. Gnatchenko², I. S. Kachur², V. G. Piryatinskaya², A. L. Sukhachev¹ and V. L. Temerov¹

¹ L. V. Kirensky Institute of Physics, Siberian Branch of Russian Academy of Sciences, 660036 Krasnoyarsk, Russian Federation
² B. Verkin Institute for Low Temperature Physics and Engineering, National Academy of Sciences of Ukraine, 61103 Kharkov, Ukraine

Corresponding author: ^a malakha@iph.krasn.ru

Received: 21 October 2010
Revised: 8 December 2010
Published online: 1 March 2011

Abstract

Optical absorption spectra of trigonal crystal TbFe₃(BO₃)₄ have been studied in the region of ⁷F₆ → ⁵D₄ transition in Tb³⁺ ion depending on temperature (2–220 K) and on magnetic field (0–60 kOe). Splitting of the Tb³⁺ excited states, both under the influence of the external magnetic field and effective exchange field of the Fe-sublattice, have been determined. Landé factors of the excited states have been found. Stepwise splitting of one of the absorption lines has been discovered in the region of the Fe-sublattice magnetic ordering temperature. This is shown to be due to the abrupt change of equilibrium geometry of the local Tb³⁺ ion environment only in the excited state of the Tb³⁺ ion. In general, the magnetic ordering is accompanied by temperature variations of the Tb³⁺ local environment in the excited states. The crystal field splitting components have been identified. In particular, it has been shown that the ground state (in D₃ symmetry approximation) consists of two close singlet states of A₁ and A₂ type, which are split and magnetized by effective exchange field of the Fe-sublattice. Orientations of magnetic moments of the excited electronic states relative to that of the ground state have been experimentally determined in the magnetically ordered state of the crystal. A pronounced shift of one of absorption lines has been observed in the vicinity of the TbFe₃(BO₃)₄ structural phase transition. The temperature interval of coexistence of the phases is about 3 K.