OSCILLATING POLARITONS IN ANTIFERROMAGNETICS WITH THE MAGNETOELECTRICEFFECT

New types of surface electromagnetic waves in tetragonal semi-infinite antiferromagnetics with the magnetoelectric effect are investigated w hen the antiferromagnetic vector is perpendicular to the surface of th e specimen and to the wave vector. It is shown that, for large values of the magnetoelectric effect, surface waves can exist both near the o scillation frequencies of the magnetic subsystem and in the range of o scillation frequencies of optical phonons. For small values of the mag netoelectric effect, surface waves exist only near the oscillation fre quencies of optical phonons, In both cases, the surface waves oscillat e, penetrating into the specimen with a period proportional to the val ue or the magnetoelectric interaction.