Magnonic crystals: towards terahertz frequencies

Abstract

This topical review presents an overview of the recent experimental and theoretical attempts on designing magnonic crystals for operation at different frequencies. The focus is put on the microscopic physical mechanisms involved in the formation of the magnonic band structure, allowed as well as forbidden magnon states in various systems, including ultrathin films, multilayers and artificial magnetic structures. The essential criteria for the formation of magnonic bandgaps in different frequency regimes are explained in connection with the magnon dynamics in such structures. The possibility of designing small-size magnonic crystals for operation at ultrahigh frequencies (terahertz and sub-terahertz regime) is discussed. Recently discovered magnonic crystals based on topological defects and using periodic Dzyaloshinskii-Moriya interaction, are outlined. Different types of magnonic crystals, capable of operation at different frequency regimes, are put within a rather unified picture.

Hybrid quantum systems based on magnonics

“…MCs represent a kind of artificial magnetic media with specific magnon properties characterized by periodical magnetic structures. The spectra of SW excitations in such magnetic media are significantly different from those in uniform media: the SW spectra of MCs exhibit features such as magnon bands where spin waves can propagate easily, as well as band gaps where spin waves are not allowed to propagate 1,61,69,70,[85][86][87] . Early studies on SWs in media with periodical magnetic structures began in the 1970s, which mainly focused on the development of microwave filters and resonators 107,108 .…”

“…In other words, studies of magnonics and magnon-based devices call for a new kind of magnetic media which possess specific magnon band structures with "valence" and "conductive" bands as well as band gaps. Thus, the concept of magnonic crystals (MCs) was put forward 61,69,70,[85][86][87] , in which spin waves (or magnons) can be modulated into magnon bands via artificial periodical structures of magnetic properties. In such a new kind of magnetic media, skyrmion based MCs (SMCs) have attracted much attention due to their dynamically tunability, topological nontrivial characteristics, as well as hybrid and quantum phenomena [88][89][90][91][92][93][94][95][96][97][98][99][100][101][102][103][104][105][106] .…”

Advances in Magnetics Roadmap on Spin-Wave Computing

“…The current state of the art is focused on the understanding of magnonic band formation in planar 1D and 2D MCs which can be fabricated by standard nano-lithographic techniques. [253], [231], [254], [255], [12] To integrate magnonic micro-and nanocircuits in the existing electronic/spintronic technology and go even beyond that, the development of large-scale three-dimensional (3D) magnetic periodic structures with high precision control of geometry and material composition at the nanometer scale, is an important challenge now. Vertically integrated 3D magnonic structures can increase the density of magnonic and spintronic elements to form scalable and configurable magnonic networks.…”

Chiral magnonic resonators: Rediscovering the basic magnetic chirality in magnonics

“…For instance, the shape anisotropy of the constituent magnetic elements could be used to produce selfbiased waveguides magnetised at an angle to the propagation direction, 47,50 influencing the coupling chirality and strength as described in items B2 and B3. Alternatively, the magnonic band structure 76 could be used explore effects associated with detuning of the resonator's frequency relative to the band gap. 77 C2.…”