Abstract

The Z type hexaferrites of Ba₃Co₂Fe₂₄O₄₁ and Sr₃Co₂Fe₂₄O₄₁ have high magnetic permeability in high frequency range so that they have been studied as candidates for frequency inductor cores and electromagnetic noise absorbers working in a gigahertz range [1]. Recently a polycrystal of Sr₃Co₂Fe₂₄O₄₁ has been found to show magnetoelectric effect even at room temperature [2]. In the present study, we measured the magnetic field dependence of the THz optical absorption spectra of a powdered polycrystal of Sr₃Co₂Fe₂₄O₄₁ at room temperature 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 [3].

© 2011 Optical Society of America