Handedness of magnetic-dipolar modes in ferrite disks

TL;DR

This paper explores the handedness of magnetic-dipolar modes in ferrite disks, revealing how symmetry breaking causes resonance coupling and describing the modes with spinor wave functions.

Contribution

It introduces a detailed analysis of helical harmonics and resonance coupling in ferrite disks, highlighting the role of symmetry breaking and field orientation.

Findings

Identification of four types of helical harmonics.

Observation of resonance coupling due to reflection symmetry breaking.

Description of mode handedness using spinor wave functions.

Abstract

For 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.