Magnetoreflection and magnetooptical Kerr effect in La$_{2/3}$Ba$_{1/3}$MnO$_{3}$ films at room temperature

Results of studies of magnetooptical Kerr effect and magnetoreflection of natural light in La$_{2/3}$Ba$_{1/3}$MnO$_{3}$/SrTiO$_{3}$ films of different thickness are presented. The Kerr effect was shown to be the most prominent in visible and near IR range; magnetoreflection was found to achieve its maximum of about 10% in the mid-IR range near the room temperature. Physical mechanisms defining the value and sign of the effects and the influence of the thin-film state on the magnetooptical properties are discussed. Magnetoreflection is estimated in the framework of the magnetorefractive effect theory.