INFLUENCE OF DYNAMIC MAGNETOELECTRIC INTERACTION ON SURFACE-POLARITONS IN FERROELECTRICS

The existence of additional transverse electric (TE) and magnetic (TM) surface polaritons formed as a result of high-frequency magnetoelectr ic interaction in a ferroelectric is predicted. The spectrum of the ne w type of surface polaritons is analyzed for transverse orientation of the electric polarization relative to the crystal surface. These pola ritons are different in ferroelectric domains with opposite directions of spontaneous electric polarization. Thus, TE surface polaritons exi st only in domains with electric polarization directed into the medium . Besides, magnetoelectric interaction induces effects like birefringe nce and anomalous dispersion of TM polaritons. Moreover, it is found t hat TM polaritons can exist in those types of ferroelectrics in which their existence was forbidden earlier. The same effects must also exis t not only in ferroelectrics, but also in ordinary dielectrics in a co nstant electric field at right angles to the crystal surface. The abov e-mentioned asymmetry of the effects, including their switching on/off , must be observed upon a change in the direction of the applied elect ric field. (C) 1998 American Institute of Physics. [S1063-777X(98)0131 0-3]