On the hyperfine interaction in rare-earth Van Vleck paramagnets at high magnetic fields

TL;DR

This paper theoretically investigates how high magnetic fields affect hyperfine interactions in Van Vleck paramagnets, specifically Tm^{3+} ions, revealing significant shell distortions that alter hyperfine fields, aligning with experimental observations.

Contribution

It introduces a theoretical model explaining the influence of high magnetic fields on hyperfine interactions in Van Vleck ions, accounting for shell distortions.

Findings

Magnetic fields induce distortions in the 4f-electron shell.

Shell distortions significantly change hyperfine magnetic fields.

The model agrees with recent experimental data.

Abstract

An influence of high magnetic fields on hyperfine interaction in the rare-earth ions with non-magnetic ground state (Van Vleck ions) is theoretically investigated for the case of $Tm^{3+}$ ion in axial symmetrical crystal electric field (ethylsulphate crystal). It is shown that magnetic-field induced distortions of $4f$-electron shell lead to essential changes in hyperfine magnetic field at the nucleus. The proposed theoretical model is in agreement with recent experimental data.