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 Sr
₃
CO
₂
Fe
₂₄
O
₄₁
at room temperature is measured, in search for a novel optical response related with magnetic property of solids. As a result, we found that Sr
₃
CO
₂
Fe
₂₄
O
₄₁
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 Ba
₂
Mg
₂
Fe
₁₂
O
₂₂
, which shows the magnetoelectric effect only at low temperatures.