We present a theory for surface polaritons on ferroelectric-antiferromagnetic materials with canted spin structure. A small uniform canted moment is allowed, resulting in a weak ferromagnetism directed in the plane parallel to the surface. Surface and bulk polariton modes for a semi-infinite film are calculated for the case of transverse electric (TE) and transverse magnetic (TM) polarization. Example results are presented using parameters appropriate for BaMnF(4). We find that the surface modes are non-reciprocal for the TE polarization due to the magnetoelectric interaction, and the non-reciprocity can be controlled by an applied electric field. Example results for attenuated total reflection (ATR) are calculated. The magnetoelectric interaction also gives rise to 'leaky' surface modes in the case of TM polarization. These are pseudo-surface waves that exist in the pass band, and dissipate energy into the bulk of the material. We show that these pseudo-surface mode frequencies and properties can be modified by temperature and the application of external electric or magnetic fields.
We calculate standing spin wave frequencies in a multilayer which unit cell is a trilayer comprised of a ferromagnet, a ferroelectric, and a normal metal. An applied voltage enhances the polarization of the ferroelectric and increases the magnetic moment at one interface through spin polarization and charge transfer. We show that the induced surface magnetism results in shifts of resonance and standing spin wave mode frequencies. A new resonance peak is predicted, associated with a strongly localized surface moment. Estimates are provided using parameters appropriate to the ferroelectric BaTiO 3 and four different ferromagnetic metals, including a Heusler alloy (Fe, CrO 2 , permalloy, and Co 2 MnGe). The calculations use an entire-cell effective-medium approximation that takes into account the polarization profile in the ferroelectric. The metallic ferromagnetic electrode is treated as a real metal, and the depolarization field is included in the determination of polarization in the ferroelectric.
The increasing of the needs of food crops raised several issues related to land use. The problems of land used caused by the lack of information related to productivity and eligibility used of land. The goal of this research is to implementation a model of Grey forecasting GM(1,1) to forecast agricultural production, especially in food crops. GM(1,1) is used to built a model with limited data samples and generate good forecasts for short libertine forecasts. This research uses data from the production of food crops for the 2004-2013 it can be calculated by using the model of GM (1,1). The results showed the model GM (1,1) can produce highly accurate forecasts, from the experimental results for pattern trends generate value ARPE 5.74% or accuracy of forecasts reached 94.26% in crop production.
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