Temperature dependence of spin reorientation and crystal-field transitions in TmFeO3 studied with terahertz transient

By employing THz time-domain spectroscopy, far infrared optical properties of TmFeO3 single crystal are investigated schematically in temperature range from 5 to 300 K. The temperature dependence of resonances due to iron ions and Tm ions absorption due to crystal field are clarified. The experimental results demonstrate that the temperature induced spin reorientation transition (SRT) as well as crystal field induced ground multiplets splitting in Tm³⁺ occur independently. In addition, the temperature dependence of beating due to antiferromagnetic resonance was observed and resolved at low temperature.