Giant magneto-optical Kerr enhancement from films on SiC due to the optical properties of the substrate

Abstract

We report a giant enhancement of the mid-infrared (MIR) magneto-optical complex Kerr angle (polarization change of reflected light) in a variety of materials grown on SiC. In epitaxially-grown multilayer graphene, the Kerr angle is enhanced by a factor of 68, which is in good agreement with Kerr signal modeling. Strong Kerr enhancement is also observed in Fe films grown on SiC and Al-doped bulk SiC. Our experiments and modelling indicate that the enhancement occurs at the high-energy edge of the SiC reststrahlen band where the real component of the complex refractive index n % passes through unity. Furthermore, since the signal is greatly enhanced when 1 n = % , the enhancement is predicted to exist over the entire visible/infrared (IR) spectrum for a free-standing film. We also predict similar giant enhancement in both Faraday (transmission) and Kerr rotation for thin films on a metamaterial substrate with refractive index 1 n = − % . This work demonstrates that the substrate used in MOKE measurements must be carefully chosen when investigating magneto-optical materials with weak MOKE signals or when designing MOKE-based optoelectronic devices.

Strong Magneto-Optical Kerr Effects in Ni-Doped ZnO Nanolaminate Structures Obtained by Atomic Layer Deposition

“…Very generally, the phenomenology of ZnO magnetism mechanisms can be separated into two groups: (i) carrier-mediated exchange interactions between the localized magnetic moments, for instance, Rudermann-Kittel-Kasuya-Yosida (RKKY) [47] or Zener double exchange; or, (ii) alternatively, the creation of spin correlated structure can be related to the electrons trapped by the nanoscale structural defects (vacancies and/or secondary phases) and leads to orbital d-shell overlapping of the neighboring TM doping atoms with the formation of bound magnetic polarons (BMP) [48]. The fact that, due to the Ni doping, an overall strong magneto-optical behavior is observed, can be explained by the simultaneous influences of various (substitutional) From another point of view, considering the nanolaminate architecture (with alter nating ZnO layer and NiO layers), we can also note a prominent optical amplification (due to interference artefacts) of the MO Kerr rotation effect observed in complex transparen ZnO/TMO multilayered structures deposited onto highly reflective substrate materia [49][50][51]. The statistical distribution of |θ Kerr | for ZnO:Ni-doped nanolaminate (Figure 9) is qualitatively and quantitatively different compared to its undoped counterpart.…”

“…From another point of view, considering the nanolaminate architecture (with alternating ZnO layer and NiO layers), we can also note a prominent optical amplification (due to interference artefacts) of the MO Kerr rotation effect observed in complex transparent ZnO/TMO multilayered structures deposited onto highly reflective substrate material [49][50][51].…”

“…Several groups of materials with a diversity of physical natures show giant MOKE polarization rotation (comparison regarding polar Kerr effect); magnetic Fabri-Pérot heterostructure [52]; ferro-, ferri-and antiferromagnetic (multiferroics, garnets) systems ( [53] and references therein); artificially nano-engineered metamaterials [54]; 2D materials [51]; nanostructured plasmonic dielectrics [55]; and topological insulators [56]. Generally, these are materials and systems that require more sophisticated process technology.…”

Wide-band enhancement of the transverse magneto-optical Kerr effect in magnetite-based plasmonic crystals

“…Yet, TMOKE has an important feature, namely it is determined by the magnetic properties of the interface and sample geometry and therefore can be used for the control of light at the nanoscale. Recent advances in nanotechnology allow one to synthesize magnetic nanostructures where the magnitude of TMOKE is significantly increased in the vicinity of optical resonances [20][21][22][23][24][25]. In particular, TMOKE enhancement has been demonstrated in magnetoplasmonic crystals [26][27][28][29][30][31][32][33] and magnetoplasmonic nanoantennas [34][35][36][37] where plasmonic resonances come into play.…”