Specific features of Nd3+ Kramers doublets' splitting in an antiferromagnetic crystal NdFe3(BO3)(4) in an external magnetic field

Gnatchenko, S. L.; Kachur, I. S.; Kurnosov, V. S.; Piryatinskaya, V. G.; Malakhovskii, V; Gudim, I. A. Source: LOW TEMPERATURE PHYSICS, 45 (8):928-933; 10.1063/1.5116545 AUG 2019

The optical absorption spectra of an easy-plane NdFe₃(BO₃)₄ antiferromagnet are measured in the region of the ⁴I_9/2 → ²H_11/2 transition of the of Nd³⁺ ion. The study is performed in the 2–35 К temperature range, in external magnetic fields of up to 65 kOe directed both along the С₃ axis and the basal plane of the crystal. The splitting values of the Nd³⁺ excited states in the exchange field of the Fe³⁺ subsystem and the g-factors of the ²H_11/2 multiplet states are determined. The nontrivial dependences of the splitting of some Nd³⁺ states in a magnetic field indicate that these states have anisotropic Fe–Nd exchange interaction.