Magnetic-field induced broadband THz absorption change in a multiferroic hexaferrite at room temperature

In the present study, the magnetic field dependence of the THz optical absorption spectra of a powdered polycrystal of Sr₃CO₂Fe₂₄O₄₁ at room temperature is measured, in search for a novel optical response related with magnetic property of solids. As a result, we found that Sr₃CO₂Fe₂₄O₄₁ has some THz absorption peaks whose optical density significantly changes under weak external magnetic fields applied by a pair of permanent magnets. The frequency range where the absorption change occurs is broader than that in the case of Ba₂Mg₂Fe₁₂O₂₂, which shows the magnetoelectric effect only at low temperatures.