Observation of Hyperfine Splitting of the Levels of V³⁺ Ions and Pairs by Phonon Spectroscopy

Abstract

In principle, frequency crossing spectroscopy¹ has a resolution limited only by the linewidths of the levels involved. In the present work measurements have been made on V³⁺ in Al₂O³ with a resolution ⪝ 100 MHz at a crossing frequency of 166 GHz. Measurements of thermal resistivity W have been made for fields along the c-axis near the crossing point at B ∿ 3.1T between the ΔM = 1 and ΔM = 2 transition frequencies of V³⁺: υ₁ = D - g_‖βB - A_HI_Z and υ₂ = 2g_‖βB + 2A_HI_Z where D = 249 GHz, g_‖ = 1.91², A_H = 288 ± 2 MHz³ and I = 7/2. Both frequencies have 8 hyperfine components which are split by A_H and 2A_H respectively. If these components are well resolved signal ΔW/W_o obtained by crossing them has 21 lines separated by A_H.