Magnetic-Sphere-Based Phononic Crystals

Abstract

Periodic arrays in one, two, and three dimensions, made of magnetic spheres embedded in a fluid matrix, are considered in this study and utilized as phononic structures. The propagation of acoustic waves through these structures is analyzed experimentally, in low-and high-frequency region, via laser vibrometry, as well as standard underwater acoustic measurements. A first comparison to theoretical calculations obtained through multiple-scattering techniques and multipole models reveals a distinct behavior depending on the immersion fluid and/or frequency regime. Our results show that the elastodynamic response of these systems can be, under conditions, simply described by classical elastic theory without taking directly (ab initio) into account the magnetic character of the spherical particles. The structures considered above could offer several possibilities including facility of construction and use in filtering applications, but they are also of interest from a theoretical point of view, as a means to investigate the validity of several approximate theoretical descriptions.

One-step polymeric phononic crystal manufacture

“…Although the theoretical research of phononic crystals is rich in numerical models, fabrications methods are rare. These broadly consist of solid sphere arrays embedded in soft matrix [21,22,23,24]. Or more recently, 3D printing technology is used for phononic crystal fabrication [25] and interference lithographic template assisted three-dimensional elastomeric network production [26,27].…”

A polymer based phononic crystal

“…Although the theoretical research of phononic crystals is rich in numerical models, fabrications methods are rare. These broadly consist of solid sphere arrays embedded in soft matrix [15,25,6,14]. Or more recently, 3D printing technology is used for phononic crystal fabrication [17].…”

Bandgap engineering of three-dimensional phononic crystals in a simple cubic lattice

“…[6][7][8] Experimental demonstrations can be found for solid cylinders 9,10 or in micromachined plates, 11,12 e.g., for thermal 13 and acoustic isolation, 14 or material defect characterization. 15 Lattices of spheres embedded in a matrix [16][17][18][19][20][21] practically demonstrated phononic bandgaps for simple 3D arrangements. More complex geometries 22 including hollow elements, 23 cellular solids with cubic symmetry, 24 or periodic bicontinuous cubic network structures 25 proved yet unfeasible to fabricate.…”