Optical Properties and Structure of Cerium Dioxide Films

Hass, G.; Ramsey, Jason; Thun, R.

doi:10.1364/josa.48.000324

Cited by 91 publications

(31 citation statements)

References 3 publications

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“…spin waves propagating along the wire axis with the wave number K with uniform cross-section distribution (at least, in the approximation KR 1). The limiting case of K = 0 corresponds to a purely magnetostatic perfectly [25], εCeO2 = 4.8 [26], εSrTiO 3 = 6.0 [27]. Analytical curves correspond to the isotropic Maxwell-Garnett approximation with εMG = 5 + 0.4i.…”

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confidence: 99%

Anomalous polarization conversion in arrays of ultrathin ferromagnetic nanowires

et al. 2015

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We study optical properties of arrays of ultrathin nanowires by means of the Brillouin scattering of light on magnons. We employ the Stokes/anti-Stokes scattering asymmetry to probe the circular polarization of a local electric field induced inside nanowires by linearly polarized light waves. We observe the anomalous polarization conversion of the opposite sign than that in a bulk medium or thick nanowires with a great enhancement of the degree of circular polarization attributed to an unconventional refraction in the nanowire medium.The study of magneto-optical response of tailored nanostructures is in the focus of active research of nanostructured materials [1][2][3]. Nonmagnetic metallic nanowires are well known in optics, and they are employed as building blocks of the so-called wire metama- Here, we study magneto-optical (MO) properties of ultrathin ferromagnetic Co nanowire arrays (see Fig. 1) by means of polarization-resolved Brillouin light scattering on magnons [11][12][13]. In a sharp contrast to the previous studies of ferromagnetic nanowires with the diameter D of 20 nm [14], here we study arrays of thin nanowires with diameter D ∼ 4.8 nm and lattice spacing ∼ 17 nm (Fig. 1). We reveal a striking anomaly of Stokes/antiStokes pattern in the spectra of Brillouin Light Scattering (BLS) from magnons in such structures. First, its asymmetry is inverted, which is impossible in principle in continuous non-structured metal layers; secondly, it is unconventionally large. Although the latter effect can be predicted formally for continuous films, such a huge asymmetry can only be calculated for materials with unrealistic optical parameters. This is explained by a strong modification of optical and magneto-optical properties for thin nanowires. While the coherent propagation of photons in the sample is weakly affected by thin wires due to their small volume concentration, the photon interaction with magnons is confined to the volume inside the wires where the wave polarization is strongly modified due to a huge mismatch in the dielectric constants of metallic nanowires and dielectric media. As a result, we observe that a linearly polarized light obliquely incident upon a metacrystal composed of ultrathin Co nanowires acquires ellipticity inside the wires that is enhanced by an order of magnitude being of the opposite sign as that in the case of continuous Co films or thicker Co wires. We visualize this effect by measuring the asymmetry of Stokes and anti-Stokes peaks in the Brillouin scattering spectra of light by the spin-wave modes of the wires, since the scattering can probe local electric fields [15]. We expect that our results will be instrumental for the emerging field of nonlinear spectroscopy of metamaterials [16] as well as for a design of novel structures with strong chiral responses [17] and polarization-sensitive light rooting [18][19][20].An array of ultrathin Co nanowires has been grown by sequential pulsed laser deposition of Co and CeO 2 in reductive conditions (P growth = 10 −5 mbar), leading to...

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confidence: 99%

Anomalous polarization conversion in arrays of ultrathin ferromagnetic nanowires

et al. 2015

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“…The resulting fits are shown in red in the plots in Figure 3 ("dispersion fit"), and the corresponding parameter values are provided in Table II. The dispersion behavior implied for undoped and 20% Sm doped ceria is summarized in Figure 4, where Fig. 4(a) compares the present results for undoped ceria with literature values, [14][15][16][17][18][19] and Fig. 4(b) compares the three films studied here to one another.…”

Section: Optical Propertiesmentioning

confidence: 58%

“…The parameters obtained from the fitting are in good agreement with the independently measured values, providing a validation of the procedures. [14][15][16][17][18][19] (b) substrate and dopant effects. Deposition on MgO(100) (Film #3) leads to a slight decrease in n relative to deposition on YSZ(100) (Film #1), likely due to poorer crystallographic registry between film and substrate creating a slightly lower density.…”

Section: Microstructural Properties a Model Validation Using Densmentioning

confidence: 99%

Determination of optical and microstructural parameters of ceria films

Oh¹,

Tokpanov²,

Hao³

et al. 2012

Journal of Applied Physics

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Optimization of Nb2O5/Ag/Nb2O5 multilayers as transparent composite electrode on flexible substrate with high figure of merit J. Appl. Phys. 112, 103113 (2012) Modulation of external electric field on surface states of topological insulator Bi2Se3 thin films Appl. Phys. Lett. 101, 223109 (2012) Ultra-thin perfect absorber employing a tunable phase change material Appl. Phys. Lett. 101, 221101 (2012) Optical properties of Mg-doped VO2: Absorption measurements and hybrid functional calculations Appl. Phys. Lett. 101, 201902 (2012) Additional information on J. Appl. Phys. Light-matter interactions are of tremendous importance in a wide range of fields from solar energy conversion to photonics. Here the optical dispersion behavior of undoped and 20 mol. % Sm doped ceria thin films, both dense and porous, were evaluated by UV-Vis optical transmission measurements, with the objective of determining both intrinsic and microstructural properties of the films. Films, ranging from 14 to 2300 nm in thickness, were grown on single crystal YSZ(100) and MgO(100) using pulsed laser deposition (both dense and porous films) and chemical vapor deposition (porous films only). The transmittance spectra were analyzed using an in-house developed methodology combining full spectrum fitting and envelope treatment. The index of refraction of ceria was found to fall between 2.65 at a wavelength of 400 nm and 2.25 at 800 nm, typical of literature values, and was relatively unchanged by doping. Reliable determination of film thickness, porosity, and roughness was possible for films with thickness ranging from 500 to 2500 nm. Physically meaningful microstructural parameters were extracted even for films so thin as to show no interference fringes at all. V C 2012 American Institute of Physics.

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“…Estimation of gold particle size from the peak absorbance of the plasmon observed using UV-vis spectroscopy (Fig. 4), using multipole scattering theory as described by Haiss et al [28] and assuming the gold particles were spherical and uncoated and the refractive index of the medium in contact with the particles was dominated by CeO 2 (~2.2 at 550 nm) [29], gave a value of 70 nm. This is far in excess of the desired size for catalytic gold nanoparticles, for instance Haider et al [30] investigated the effect gold nanoparticle size had on the catalytic activity of Au/TiO 2 and Au/CeO 2 where the gold particles ranged in size from 1.3-11.3 nm and it was found that the highest catalytic activity emerged for an average particle size of 6.9 nm.…”

Section: Contributed Articlementioning

confidence: 99%

AACVD synthesis of catalytic gold nanoparticle‐modified cerium(IV) oxide thin films

Evans

Maggio

Blackman

et al. 2015

Phys. Status Solidi C

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Co‐deposition of Ce(dbm)4 and NH4AuCl4 precursors in acetone at 500 °C via AACVD results in deposition of crystalline CeO2 thin films containing/decorated with metallic gold. These particles are estimated to be ∼ 70 nm in size via optical methods. Preliminary testing of catalytic activity showed the materials were surprisingly catalytically active given the very small amounts of gold present and the large estimated particle size, although the presence of smaller catalytically active particles could not be discounted. (© 2015 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

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Optical Properties and Structure of Cerium Dioxide Films

Cited by 91 publications

References 3 publications

Anomalous polarization conversion in arrays of ultrathin ferromagnetic nanowires

Anomalous polarization conversion in arrays of ultrathin ferromagnetic nanowires

Determination of optical and microstructural parameters of ceria films

AACVD synthesis of catalytic gold nanoparticle‐modified cerium(IV) oxide thin films

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