Tuning the Band Structures of a 1D Width-Modulated Magnonic Crystal by a Transverse Magnetic Field

TL;DR

This study explores how a transverse magnetic field influences the band structure of a 1D width-modulated magnonic crystal, revealing tunable and switchable bandgaps crucial for dynamic spin-wave device design.

Contribution

It demonstrates the impact of magnetization direction on magnonic band structures and introduces field-tunable bandgap control using theoretical techniques.

Findings

Bandgaps exhibit non-monotonic, large field-tunability.

Some bandgaps can be switched on/off by adjusting the magnetic field.

Magnetization direction significantly affects spin-wave excitation efficiency.

Abstract

Theoretical studies, based on three independent techniques, of the band structure of a one-dimensional width-modulated magnonic crystal under a transverse magnetic field are reported. The band diagram is found to display distinct behaviors when the transverse field is either larger or smaller than a critical value. The widths and center positions of bandgaps exhibit unusual non-monotonic and large field-tunability through tilting the direction of magnetization. Some bandgaps can be dynamically switched on and off by simply tuning the strength of such a static field. Finally, the impact of the lowered symmetry of the magnetic ground state on the spin-wave excitation efficiency of an oscillating magnetic field is discussed. Our finding reveals that the magnetization direction plays an important role in tailoring magnonic band structures and hence in the design of dynamic spin-wave switches.