Handedness of magnetic-dipolar modes in ferrite disks

Abstract

AbsractFor magnetic-dipolar modes in a ferrite, components of the magnetic flux density in a helical coordinate system are dependent on both an orientation of a gyration vector and a sign of a pitch. It gives four types of helical harmonics for magnetostatic-potential wave functions in a ferrite disk. Because of the reflection symmetry breaking, coupling between certain types of helical harmonics takes place in the reflection points. The reflection feature leads to exhibition of two types of resonances: the "right" and "left" resonances. These resonances become coupled for a ferrite disk placed in a homogeneous tangential RF magnetic field. One also observes such resonance coupling for a ferrite disk with a symmetrically oriented linear surface electrode, when this ferrite particle is placed in a homogeneous tangential RF electric field. In a cylindrical coordinate system handedness of magnetic-dipolar modes in a ferrite disk is described by spinor wave functions.

Coupled states of electromagnetic fields with magnetic-dipolar-mode vortices: Magnetic-dipolar-mode vortex polaritons

“…While creation of a full-wave electromagnetic field analysis of helicity in MDM-vortex polaritons entails great difficulties (because of nonintegrability, i.e. path-dependence of the problem), This shows that proper spectral problem solutions for MDMs should be obtained in a helical coordinate system [22,30]. The helices are topologically nontrivial structures and the phase relationships for waves propagating in such structures could be very special.…”

“…In an analysis of the MS-wave propagation in a helical coordinate system in Refs. [22,30], the Waldron's coordinate system was used [31].…”

“…In the Waldron helical system ( ) , , r φ ζ , the Walker equation for MS-potential wave function [11] has a form [22,30]:…”

“…For an outside region ( r ≥ ℜ ) one has: are amplitude coefficients. It was shown [22,30] that for a given direction of a bias magnetic field (oriented along a disk axis) there exist two types of double-helix resonances in a quasi-2D ferrite disk. One resonance state is specified by the (1) (4) ψ ψ ↔ phase correlation, when a closed-loop phase way is due to equalities for the wave numbers: (1) Another resonance state is specified by the (2) (3) ψ ψ ↔ phase correlation with a closed-loop phase way due to equalities for the wave numbers: (2) (3)…”

“…The helical-mode resonances of lossless magneto-dipole oscillations in a ferrite disk are not characterized by the orthogonality relations. It can be shown that for two helices giving a doublehelix resonance in a ferrite disk there are deferent power flow densities [30]. Moreover, for such modes there are no properties of parity ( P ) and time-reversal ( T ) invariance -the PTinvariance.…”