Using magnetic hyperbolic metamaterials as high frequency tunable filters

Macêdo, Rair; Livesey, Karen L.; Camley, R. E.

doi:10.1063/1.5049602

Cited by 23 publications

(14 citation statements)

References 53 publications

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“…Here, we have concentrated on natural structures, which require large fields in order to achieve significant tunability. However, similar behavior should be expected in recently investigated artificial structures based on the same principles [29].…”

Section: Surface Polaritonssupporting

confidence: 79%

Engineering terahertz surface magnon-polaritons in hyperbolic antiferromagnets

Macêdo

Camley

2019

Phys. Rev. B

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Magnetic crystals were recently studied as a route to hyperbolic dispersion and the effects associated with it. These studies, however, concentrated on bulk waves and frequencies where transmission is possible and where negative refraction occurs. Here, in contrast, we concentrate on geometries which sample regions of the dispersion relations where bulk propagation is not possible. This is done by controlling the orientation of the uniaxial anisotropy axis with respect to the surface of the crystal. Furthermore, we find that new magnetic surface polaritons exist in these regions, and we investigate the nature of these waves. In addition, significant tunability can be introduced by applying an external field perpendicular to the easy axes of a uniaxial antiferromagnet, creating a canted structure and generally shifting the frequencies to higher values. This externally applied field dramatically changes the nature of both surface and bulk polaritons, making them highly nonreciprocal.

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Section: Surface Polaritonssupporting

confidence: 79%

Engineering terahertz surface magnon-polaritons in hyperbolic antiferromagnets

Macêdo

Camley

2019

Phys. Rev. B

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“…This frequency is interesting for creating band pass filters. [52,53] We consider varying the electrical conductivity σ of the composite. Results are shown in Fig.…”

Section: Resultsmentioning

confidence: 99%

Far-Infrared Reflection from Heterostructures Made of Ultrathin Ferromagnetic Layers

et al. 2019

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Recent progress has been made in creating terahertz magnons using ultrathin ferromagnetic layers. Due to their short lifetimes, these can be difficult to measure. Here we detail a calculation that shows that infrared magnons can be detected using standard reflection and attenuated total reflection measurements from a thin film heterostructure made up of alternating ultrathin magnetic and nonmagnetic layers. We use an entire-cell effective medium calculation to find the magnetic permeability of the heterostructure and then use electromagnetic boundary conditions to calculate reflectivity as a function of frequency. There are appreciable dips in the reflectivity at infrared magnon resonance frequencies, for realistic material parameters. Moreover, the strong coupling of magnon-photons indicates the possible use of 50 GHz -1 T Hz magnons in integrated signal processing devices.

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“…For example, in Fig. 16(a) we show a multilayer structures comprising magnetic layers separated by a nonmagnetic spacer layer [47]. By controlling the thickness of the spacer layer it is possible to induce antiferromagnetic coupling, and therefore generate spin canting by means of an externally applied field.…”

Section: Discussionmentioning

confidence: 99%

Electromagnetic Waves in Canted Magnets

Macêdo¹,

Stamps²

2020

Compendium on Electromagnetic Analysis

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The optical properties of canted antiferromagnetics is discussed from the perspective of magnetic polaritons and field tunable electromagnetic properties. Canted antiferromagnets have a weak magnetization and their electromagnetic properties can be affected by applied magnetic and in the case of multiferroics, applied electric fields. A theoretical approach is outlined here that is useful for describing the THz frequency electromagnetic response and properties of a large variety of canted spin systems. The properties of two example systems are discussed: an antiferromagnet with canted induced through an externally applied magnetic field, and an antiferromagnetic multiferroic wherein the magnetic sublattices are canted by an internal coupling to a spontaneous dielectric polarisation.

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Using magnetic hyperbolic metamaterials as high frequency tunable filters

Cited by 23 publications

References 53 publications

Engineering terahertz surface magnon-polaritons in hyperbolic antiferromagnets

Engineering terahertz surface magnon-polaritons in hyperbolic antiferromagnets

Far-Infrared Reflection from Heterostructures Made of Ultrathin Ferromagnetic Layers

Electromagnetic Waves in Canted Magnets

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