Tunable strong magnon-magnon coupling in two-dimensional array of diamond shaped ferromagnetic nanodots

Abstract

Hybrid magnonics involving coupling between magnons and different quantum particles have been extensively studied during past few years for varied interests including quantum electrodynamics. In such systems, magnons in magnetic materials with high spin density are utilized where the “coupling strength” is collectively enhanced by the square root of the number of spins to overcome the weaker coupling between individual spins and the microwave field. However, achievement of strong magnon-magnon coupling in a confined nanomagnets would be essential for on-chip integration of such hybrid systems. Here, through intensive study of interaction between different magnon modes in a Ni80Fe20 (Py) nanodot array, we demonstrate that the intermodal coupling can approach the strong coupling regime with coupling strength up to 0.82 GHz and cooperativity of 2.51. Micromagnetic simulations reveal that the intermodal coupling is mediated by the exchange field inside each nanodot. Micromagnetic Simulations reveal that anticrossing occurs due to change in exchange configuration (Symmetry breaking). The coupling strength could be continuously tuned by varying the bias field (Hext) strength and orientation (φ), opening routes for external control over hybrid magnonic systems. These findings could greatly enrich the rapidly evolving field of quantum magnonics.

Using magnons as a quantum technology platform: a perspective

“…Recognizing these challenges, the field underwent a transition towards nanoscale magnonics, driven by the aspiration for enhanced miniaturization and compatibility with complementary metal-oxidesemiconductor technology. In response to the identified gaps in current research, recent literature has made substantial strides in unveiling the intricate phenomenon of magnon-magnon coupling within irregularly shaped hexagonal dots [50], triangular [61], diamond nanodots [62], cross-shaped nanomagnets [63][64][65], and nanoring arrays [66]. These investigations represent a pivotal advancement towards bridging the existing knowledge deficiencies in the field.…”

“…Moreover, g, governed by magnon-magnon interactions, is controllable through diverse methods such as adjusting magnetic element size, i.e. by device engineering [50,65], external magnetic fields [10,19,61], or amplitude of rf excitation [61,62], enhancing information propagation optimization. This tunability not only regulates magnon interactions but also influences coherent information transfer efficiency, contributing to the adaptability and versatility of magnonic devices across varied operational requirements [2,12].…”

“…Magnon-magnon coupling research explores a vast spectrum of intricacies, traversing from millimeter-sized 3D cavities [9,17,129] to thin-film and heterostructure configurations [14,48,55,87], further delving into magnetic nanostructures [50,[61][62][63][64][65][66][67][68], and ultimately reaching the realm of an array of single qubits [86,88,89]. Weak coupling and limited spin numbers pose intrinsic limitations.…”