Vincensius Gunawan

TE and TM modes polaritons in multilayer system comprise of a PML-type magnetoelectric multiferroics and ferroelectrics

In this paper, we report our study on both bulk and surface polaritons generated in Multilayer system. The multilayer consists of ferroelectric and multiferroic with canted spins structure. The effective medium approximation is employed to derive the dispersion relation for both bulk and surface modes. Surface and bulk polaritons are calculated numerically for the case of Transverse electric (TE) and Transverse magnetic (TM) modes. Example results are presented using parameters appropriate for BaMnF4/BaAl2O4. We found in both TE and TM modes, that the region where the surface modes may exist is affected by the volume fraction of the multiferroics. The region of the surface modes decrease when the volume fraction of the multiferroic is reduced. This region decrement suppress the surface polariton curves which result in shortening the surface modes curves.

Structural characterization of hydrothermally synthesized MnO2 nanorods

We prepared the hydrothermal method to synthesize MnO2 nanorods with controlled structure. KMnO4 and HCl with the various molar ratio (1:2,1:6,1:8) reacted at 160°C for three hours to form MnO2 nanorods. The study found that changing the molar ratio can control the structure and morphology of MnO2. The result revealed that MnO2 formed in nanorod microstructures with different crystallographic structure and phase composition of each molar ratio. The diffraction peaks observed at 2θ values of 28.9°, 37.8°, 40.9°, 49.7° and 60.5° respectively indexed to (110), (101), (200), (411) and (521) plane reflections of a tetragonal phase of β-MnO2 and α-MnO2. The characterization of the morphology showed that the diameters of nanorod microstructures of MnO2 ranging from 30 to 145 nm with length ranging from 0.5 to 3 μm. These MnO2 nanorods product would be potentially used in energy storage devices.

Polaritons in magnetoelectric multiferroics films: Switching magnon polaritons using an electric field

ABSTRACT We present a theoretical study of polarions on the magnetoelectric multiferroics with finite thickness (film) geometry. The multiferroics are ferroelectric-antiferromagnet with canted spin structure. Dispersion relation for surface and bulk polaritons are calculated for the case of transverse electric (TE) polarization. Example results are presented using parameters appropriate for BaMnF4. It is found that bulk polaritons posses discreet character due to the film geometry. We also found that there are two branches of surface polaritons which are reciprocal. Example results for attenuated total reflection (ATR) are also presented. Analyzing the ATR reflection, we found that the branches of surface polaritons are able to be switched by applying an electric field opposite to the polarization.