Large magneto-optic enhancement in ultra-thin liquid-phase-epitaxy iron garnet films

Levy, M.; Chakravarty, Ashim; Huang, Heqing; Osgood, Richard M.

doi:10.1063/1.4926409

Cited by 23 publications

(9 citation statements)

References 24 publications

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“…The comparison between experimental and theoretical results indicates that the magneto‐optical response of nanostructured Ni is much stronger (approximately ten times) than that of its bulk counterpart. Similar increase has been previously reported in larger‐diameter Ni nanowire media with the magneto‐optical response approximately five times stronger than that expected from a bulk material response and in ultrathin Iron Garnett films . The results suggest that nanostructured Ni can provide further enhancement of magneto‐optical response.…”

Section: The Enhanced Faraday Effectsupporting

confidence: 88%

Magneto‐Optical Metamaterials: Nonreciprocal Transmission and Faraday Effect Enhancement

Fan

Nasir

Nicholls

et al. 2019

Advanced Optical Materials

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the effective medium regime, known for its tolerance to small-scale geometry variations. [9][10][11][12][13] We present comprehensive theoretical, experimental, and numerical analysis of the electromagnetic properties of the magneto-optical metamaterial, demonstrating both the rotation of the polarization plane and nonreciprocal transmission, two phenomena that can be controlled by the direction of the external magnetic field. This enhanced response is the result of the combination of the introduced magneto-optical properties and strong anisotropy of the metamaterial. We demonstrate rotation of the polarization plane with the effective Verdet constant equivalent of at least 10 5 rad m −1 T −1 , significant enhancement with respect to bulk ferromagnetic materials, [14] suggesting that nanostructured magnetic materials have much stronger magneto-optical response than their bulk counterparts. Overall, plasmonic magneto-optical nanorods combine the benefits of sub-wavelength light manipulation offered by metamaterials and of strong magneto-optics offered by plasmonic nanocomposites, leading to a promising material platform for integrated nanophotonic applications.The magneto-optical metamaterial geometry and its optical response are illustrated in Figure 1. The composite is formed by an array of aligned plasmonic (gold) nanorods with magnetooptical (nickel) shells inside a dielectric (alumina) matrix (note that in the composites the Ni shells extend only part-way along the rod; see the Experimental Section). As follows from the geometry, in the absence of an external static magnetic field and in the limit when the unit cell is much smaller than the wavelength (a << λ 0 ), the optical response of the composite can be described by a diagonal permittivity tensor with Cartesian components = ⊥ ⊥ zẑ { , , }     . Effective medium theory can be used to relate the components of the effective permittivity  ⊥ and  zz to the permittivity of the constituent materials as well as to the geometrical parameters of a metamaterial, such as a unit cell a, and radii of the rod r 1 and of the shells around the rod r i , with i = 2, …, N. Existing analytical and numerical tools allow calculations of the optical response of metamaterials composed of rods without shells, with plasmonic and magneto-optical material constituents and in the limit r 1 << a, [1,11,13,15] as well as shelled nanorod composites, comprising nonmagneto-optical materials with arbitrary rod concentration. [12,16] Here, we present a formalism that can incorporate magneto-optical response in the effective-medium description of shelled rod metamaterials and even in the limit  r a i 2 . We consider a metamaterial with a = 64 nm, r 1 = 15 nm, and r 2 = 23 nm and assume that the Magneto-optical effects are at the heart of modern technologies providing opportunities for polarization control in laser physics and optical communications, metrology, and in high-density data storage. Here a new type of a hyperbolic magneto-optical metamaterial based on Au-Ni nanorod arrays ...

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Section: The Enhanced Faraday Effectsupporting

confidence: 88%

Magneto‐Optical Metamaterials: Nonreciprocal Transmission and Faraday Effect Enhancement

Fan

Nasir

Nicholls

et al. 2019

Advanced Optical Materials

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“…magnetization of 4πMs=1800 G. All the samples were obtained from the same original magnetic film by a sequential etching in an ortho-phosphoric acid bath with a slow-rotation rate to ensure uniform thickness[14]. Thickness uniformity was verified by probing different points of the sample surface via transmission electron microscopy.…”

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confidence: 99%

“…The magneto-optical response of the ultra-thin films evinces some peculiarities. In particular, the specific Faraday rotation in iron-garnet films has been found to grow as the thickness decreases down to tens of nanometers [14]. Such increase might be due to a larger magneto-optical gyrotropy parameter near the film interface than in the bulk.…”

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confidence: 99%

TMOKE as efficient tool for the magneto-optic analysis of ultra-thin magnetic films

Borovkova

Hashim

Kozhaev

et al. 2018

Applied Physics Letters

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Ultra-thin magnetic dielectric films are of prime importance due to their applications for nanophotonics and spintronics. Here we propose an efficient method for the magneto-optical investigation of ultra-thin magnetic films that allows one to access their state of magnetization and magneto-optical properties. It is based on the surface-plasmon-polariton-assisted transverse magneto-optical Kerr effect (TMOKE). In our experiments sub-100nm-thick bismuth-substituted lutetium iron-garnet films covered with a plasmonic gold grating have been analyzed. The excitation of surface plasmon-polaritons provides resonance enhancement of TMOKE up to 0.04 and makes it easily detectable in experiment. For films thicker than 40 nm the TMOKE marginally depends on the film thickness. Further decrease of the film thickness diminishes TMOKE since for such thicknesses the surface plasmon-polariton field partly penetrates inside the nonmagnetic substrate. Nevertheless, the TMOKE remains measurable even for few-nm-thick films, which makes this technique unique for the magneto-optical study of ultra-thin films. Particularly, the proposed method reveals that the off-diagonal components of the magnetic film permittivity tensor grow slightly with the reduction of the film thickness.Currently, ultra-thin ferrimagnetic dielectric films are of significant interest due to their applications in nanophotonics, magnonics and spintronics [1][2][3][4][5][6]. Magnetic dielectrics like bismuthsubstituted iron-garnets have outstanding optical properties in the near infrared where they evince low optical absorption and a relatively large magneto-optical response [7][8][9][10]. Practical use of spintronic devices for magnetic information recording requires magnetic field confinement in the

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“…The magnetic field is expressed in terms of the current in the electromagnet. Reprinted with permission from: ref [1]. Fig.…”

mentioning

confidence: 99%

“…Raman shifts as a function of film thickness showing enhancement in intensity ratio and shifts in relative peak position. Reprinted with permission from: ref [1]. Fig.…”

mentioning

confidence: 99%

Geometry Induced Magneto-Optic Effects in Lpe Grown Magnetic Garnet Films

Chakravarty¹

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Large magneto-optic enhancement in ultra-thin liquid-phase-epitaxy iron garnet films

Cited by 23 publications

References 24 publications

Magneto‐Optical Metamaterials: Nonreciprocal Transmission and Faraday Effect Enhancement

Magneto‐Optical Metamaterials: Nonreciprocal Transmission and Faraday Effect Enhancement

TMOKE as efficient tool for the magneto-optic analysis of ultra-thin magnetic films

Geometry Induced Magneto-Optic Effects in Lpe Grown Magnetic Garnet Films

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