Micro-Structured Ferromagnetic Tubes for Spin Wave Excitation

TL;DR

This paper investigates micron-scale ferromagnetic tubes on spin waveguides, demonstrating a tenfold increase in spin wave amplitude but requiring high bias fields and only exciting the uniform mode.

Contribution

It introduces a novel use of ferromagnetic tubes to enhance spin wave excitation in waveguides, showing significant amplitude improvement.

Findings

Tenfold increase in spin wave amplitude

High bias magnetic fields needed for operation

Only the uniform spin wave mode is excited

Abstract

Micron scale ferromagnetic tubes placed on the ends of ferromagnetic CoTaZr spin waveguides are explored in order to enhance the excitation of Backward Volume Magnetostatic Spin Waves. The tubes produce a closed magnetic circuit about the signal line of the coplanar waveguide and are, at the same time, magnetically contiguous with the spin waveguide. This results in a 10 fold increase in spin wave amplitude. However, the tube geometry distorts the magnetic field near the spin waveguide and relatively high biasing magnetic fields are required to establish well defined spin waves. Only the lowest (uniform) spin wave mode is excited.