Magnetic control of a meta-molecule

Abstract

Metamaterials offer the prospect of new science and applications. They have been designed by shaping or changing the material of the individual meta-molecules to achieve properties not naturally attainable. Composite meta-molecules incorporating a magnetic component offer new opportunities. In this work we report on the interaction between a non-magnetic split ring resonator (SRR) and a thin film of yttrium iron garnet (YIG). Strong hybridized resonances are observed. While the SRR is characterized by a magnetic and electric resonance, in practice, it is found that the YIG couples strongly to this symmetric (electric) mode of the SRR. It is also demonstrated that the anti-crossing region provides fertile ground for the creation of elementary excitations such as backward volume magnetostatic waves.

Rigorous numerical study of strong microwave photon-magnon coupling in all-dielectric magnetic multilayers

“…By analogy with SRR-based metamaterials loaded with bulk YIG [16], it would be logical to expect a larger magnon mode peak intensity in thicker YIG layers sandwiched between two HDC layers. On one hand, the strength of the interaction between spins and an electromagnetic field mode scales as the square root of the total number of spins [34].…”

“…al. Most significantly, they do not discuss the mode anti-crossing effect that lies at the heart of magnetically tuneable materials and microwave quantum systems [16,17,[23][24][25][26][27][28]. In fact, the anti-crossing could not be observed in the experimental arrangement used by Bai et.…”

“…[31]) and in magnetically tunable microwave metamaterials in particular (see, e.g., Refs. [14][15][16][17][18][19]). SRR-based devices represent a magnetic film-loaded SRR that is excited by a microstrip or coplanar line (for brevity and generality, hereafter we also use the term "stripline").…”

Magnetic spheres in microwave cavities

“…Indeed, strongly coupled microwave photons with magnons have been experimentally reported for either YIG films with broadband coplanar waveguides (CPWs) [18][19][20], or YIG spheres in 3D microwave cavities [21][22][23]. A series of anticrossings were observed in thicker YIG films and split rings [19,20]. The coupling of magnons in YIG spheres with a superconducting qubit via a mircowave cavity mode in the quantum limit has been reported [21].…”

“…YIG has spin density of 2×10 22 cm −3 [14], and the Gilbert damping (reciprocal quality) factor of the magnetization dynamics ranges from 10 −5 to 10 −3 [15][16][17], which facilitates strong coupling for smaller samples. Indeed, strongly coupled microwave photons with magnons have been experimentally reported for either YIG films with broadband coplanar waveguides (CPWs) [18][19][20], or YIG spheres in 3D microwave cavities [21][22][23]. A series of anticrossings were observed in thicker YIG films and split rings [19,20].…”