Magnons and crystal field transitions in hexagonal REMnO3 (RE = Er, Tm, Yb, Lu) single crystals

TL;DR

This study investigates the magnetic excitations and crystal field transitions in hexagonal REMnO3 single crystals, revealing how magnon frequencies and magnetic interactions vary with different rare-earth ions and external magnetic fields.

Contribution

It provides detailed measurements of magnon and crystal field frequencies, oscillator strengths, and g-factors in REMnO3, highlighting systematic trends and magnetic interactions involving RE ions.

Findings

Magnon frequency increases as RE ion radius decreases.

RE magnetic ordering occurs below 3.5 K and under strong magnetic fields.

Magnetic interactions include exchange between Mn3+ spins and RE3+ moments.

Abstract

Far-infrared optical transmission spectra of the antiferromagnetic resonances, or magnons, and crystal field transitions have been studied in hexagonal REMnO3 (RE = Er, Tm, Yb, Lu) single crystals. The magnon and CF frequencies, their oscillator strengths, and effective g-factors have been measured using external magnetic fields up to 9 T in the temperature range between 1.5 K and 100 K. The magnon frequency increases systematically with a decrease of the RE ion radius. The magnetic ordering of RE ions (RE=Er, Tm, Yb) was observed at low temperatures T<3.5 K and in strong external magnetic fields. The observed effects are analyzed taking into account main magnetic interactions in the system including exchange of the Mn3+ spins with RE3+ paramagnetic moments.