Magnetoelectric and multiferroic materials are promising building blocks for energy-efficient memory devices as they allow electric-field control of the magnetic order. In this thesis, I focused on the dynamic magnetoelectric effect, which gives rise to electric-dipole-active magnon excitations and non-reciprocal light absorption. I studied the spin excitations of several magnetoelectric and multiferroic compounds such as Y- and Z-hexaferrites, Ba2CoGe2O7 and LiCoPO4, by infrared and terahertz spectroscopy. Based on the measured spectra, I determined the selection rules of the spin excitations and found electromagnon as well as magnetoelectric spin excitations. For magnetoelectric spin excitations, I observed non-reciprocal light absorption that I used it to detect antiferromagnetic domains of Ba2CoGe2O7 and LiCoPO4. Finally, I demonstrated the control of the magnetic order and domain composition by static (in Ba2CoGe2O7) as well as by oscillating electric and magnetic fields [in LiCoPO4 and possibly in Y-hexaferrite Ba0.2Sr1.8Co2(Fe0.96Al0.04)12O22]
(seminar organized by the Department of Dielectrics)