Chapters authored
Radiation and Propagation of Waves in Magnetic Materials with Helicoidal Magnetic Structure
In this chapter, we are shortly reviewing some problems of electromagnetic and acoustic wave propagation and radiation in the magnets with helicoidal spin structure. We show the band structure of the coupled wave spectrum in the materials. The band gap width depends on the spiral angle (or, equivalently, on external magnetic field value). Interaction of spin and electromagnetic waves leads to opening the gap in spin-electromagnetic dispersion. This gap leads to opacity window in reflection spectrum of spiral magnet plate. The opacity window closes at phase transition into collinear ferromagnetic state and reaches a maximum at simple spiral state. At the frequencies near band gap boundaries, the rotation of polarization plane of propagating electromagnetic wave is observed. Account of interaction of spin and electromagnetic waves with acoustic subsystem leads to opening the gap in spin-acoustic spectrum. This gap leads to some features in electromagnetic reflectance spectrum and to rotation of acoustic wave polarization plane, i.e. to acoustic Faraday effect. We also show the possibility of acoustic and electromagnetic wave radiation by helicoidal magnets at phase transition into collinear ferromagnetic state. Some features of electromagnetic waves generation by spiral magnets placed in homogeneous magnetic field with harmonical time-dependence are also discussed.
Part of the book: Magnetic Materials
Magneto‐Plasmonics and Optical Activity in Graphene‐Based Nanowires
Nowadays, graphene plasmonics shows a great number of features unusual for traditional (metal‐based) plasmonics from high localization and large propagation distance of surface plasmon‐polaritons (SPPs) through the existence of both TE‐ and TM‐polarized SPPs to the possibility of controlled SPPs by graphene chemical potential (or, equivalently, by gate voltage or chemical doping). Cylindrical graphene‐based plasmonic structures have some advantages in contrast to planar geometry: absence of edge losses, existence of high‐order azimuthal modes, etc. In this work, we discuss some ways to obtain an optical activity in cylindrical graphene‐based plasmonic structures and its possible applications to SPPs manipulation.
Part of the book: Nanoplasmonics