Spin Wave Electromagnetic Nano‐Antenna Enabled by Tripartite Phonon‐Magnon‐Photon Coupling

Abstract

Tripartite coupling between phonons, magnons, and photons in a periodic array of elliptical magnetostrictive nanomagnets delineated on a piezoelectric substrate to form a 2D two‐phase multiferroic crystal is investigated. Surface acoustic waves (SAW) (phonons) of 5–35 GHz frequency launched into the substrate cause the magnetizations of the nanomagnets to precess at the frequency of the wave, giving rise to confined spin‐wave modes (magnons) within the nanomagnets. The spin waves, in turn, radiate electromagnetic waves (photons) into the surrounding space at the SAW frequency. Here, the phonons couple into magnons, which then couple into photons. This tripartite phonon‐magnon‐photon coupling is thus exploited to implement an extreme sub‐wavelength electromagnetic antenna whose measured radiation efficiency and antenna gain exceed the approximate theoretical limits for traditional antennas of the same dimensions by more than two orders of magnitude at some frequencies. Micro‐magnetic simulations are in excellent agreement with experimental observations and provide insight into the spin‐wave modes that couple into radiating electromagnetic modes to implement the antenna.

A spintronic analog of the Landauer residual resistivity dipole on the surface of a topological insulator containing a line defect *

“…This will happen only of the frequency is low enough that the time variation of the field can keep up with the time variation of the current. The oscillating magnetic field too can radiate electromagnetic waves, making the line defect act as a miniature antenna [14][15][16][17]. These radiations can be detected with suitable detectors.…”

Bias field orientation driven reconfigurable magnonics and magnon−magnon coupling in triangular shaped Ni80Fe20 nanodot arrays

“…The fundamental understanding of spin waves (SWs) in myriads of MCs have been explored and number of SWbased miniaturized microwave components and devices have been introduced during the last decade. These include filters [33], transistors [34], multiplexers [35], splitters [36], interferometers [8], gratings [37], waveguides [38], phase shifters [39], nanograting couplers [40], directional couplers [41] nanomagnetic antennae [42,43] and neuromorphic computing [44]. In nanodot arrays, inhomogeneous internal field and interdot interaction [45,46] can efficiently control their magnetic properties, leading towards complex spin configurations and SWs within the nanomagnet array [23,[47][48][49].…”

Acousto‐Plasmo‐Magnonics: Coupling Spin Waves with Hybridized Phonon‐Plasmon Waves in a 2D Artificial Magnonic Crystal Deposited on a Plasmonic Material

“…These types of modes (the acoustic type), which we call hybrid (acoustic) phononplasmon modes, can magneto-elastically couple into magnon modes in magnetostrictive nanomagnets when their frequencies are similar in magnitude. Magneto-elastic coupling of pure phonon modes with magnon modes (magnon-phonon coupling) in magnetostrictive nanomagnets has been widely studied, both theoretically and experimentally, [17][18][19][20][21][22][23][24] but we are not aware of any experimental study involving coupling between the hybrid phonon-plasmon modes and magnon modes, which is essentially tripartite phonon-plasmon-magnon coupling. Strong coupling can result in this case, with cooperativity factor far exceeding unity (as we show later).…”