Reconfigurable Spin-Wave Properties in Two-Dimensional Magnonic Crystals Formed of Diamond and Triangular Shaped Nanomagnets

TL;DR

This study investigates how the shape and magnetic bias influence spin-wave dynamics in two-dimensional magnonic crystals made of diamond and triangular nanodots, revealing shape-dependent tunability crucial for future device applications.

Contribution

It provides the first comparative experimental analysis of shape-dependent reconfigurable magnetization dynamics in non-ellipsoidal nanodot structures using broadband ferromagnetic resonance spectroscopy.

Findings

Diamond nanodots show symmetric to skewed to discontinuous dispersion transitions.

Triangular nanodots exhibit anti-crossing of SW modes at specific angles.

Shape and bias field critically affect spin-wave spectra and potential device functionalities.

Abstract

Two-dimensional ferromagnetic nanodot structures exhibit intriguing magnetization dynamics and hold promise for future magnonic devices. In this study, we present a comparative experimental investigation into the reconfigurable magnetization dynamics of non-ellipsoidal diamond and triangular-shaped nanodot structures, employing broadband ferromagnetic resonance spectroscopy. Our findings reveal substantial variations in the spin wave (SW) spectra of these structures under different bias field strengths (H) and angles ({\phi}). Notably, the diamond nanodot structure exhibits a variation from nearly symmetric W-shaped dispersion to a skewed dispersion and subsequent transition to a discontinuous dispersion with subtle variation in bias field angle. On the other hand, in the triangular nanodot array a SW mode anti-crossing appears at {\phi} = 15{\deg} which is starkly modified with the increase in {\phi} to 30{\deg}. By analyzing the static magnetic configurations, we unveil the nature of the SW spectra in these two shapes. We reinforce our observations with simulated spatial power and phase maps. This study underscores the critical impact of dot shape and inversion symmetry on SW dynamical response, highlighting the significance of selecting appropriate structures and bias field strength and orientation for required functionalities. The remarkable tunability demonstrated by the magnonic crystals underscores their potential suitability for future magnonic devices.