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T. Rouiller

Bio: T. Rouiller is an academic researcher from Jean Monnet University. The author has contributed to research in topics: Barium ferrite & Isolator. The author has an hindex of 5, co-authored 10 publications receiving 113 citations.

Papers
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Journal ArticleDOI
TL;DR: In this article, Barium hexaferrite (BaFe12O19 or BaM) thick films are deposited here using a RF sputtering system, and they are amorphous and non magnetic after the deposition.

33 citations

Journal ArticleDOI
TL;DR: In this paper, the authors developed an integrated and self-biased coplanar isolator using barium ferrite sputtered films, 1-36 mum thick, which were deposited under optimized conditions by radio frequency magnetron sputtering on alumina substrates.
Abstract: The development of passive devices using a ferrite is a major focus of current research for electronic applications in the microwave range (circulators and isolators). Hexagonal ferrite, such as barium ferrite (BaFe12O19 or BaM), which has a large resistivity and high permeability at high frequencies are indeed of great interest for microwave device applications. In this work we developed an integrated and self-biased coplanar isolator using BaM sputtered films. BaM films, 1-36 mum thick, were deposited under optimized conditions by radio frequency magnetron sputtering on alumina substrates. The films were crystallized using a 800degC thermal annealing. Isolators were then realized using patterning of coplanar waveguides (CPW) with standard lift-off technique. The slots and the central width were 300 mum wide and gold was used for the conductor lines. We evaluated the influence of various parameters on the device performances: the magnetic film's thickness, the positioning of the magnetic film (CPW deposited onto the magnetic film or directly on the substrate), the CPW metallic thickness and the polarizing field. As standard design, the CPW were deposited on the top of the magnetic film. At the remanent magnetization (no polarizing field applied), the transmission coefficients then showed a non reciprocal effect, which reached 5.4 dB per cm of line length at 50 GHz for a 26.5 mum thick BaM film. Both the insertion losses and the non-reciprocal effect measured increased with the magnetic film thickness with a saturation effect. In the second design where the CPW is deposited directly on the substrate after a selective etching of the BaM film, we measured that the non reciprocal effect reached higher values for lower BaM thicknesses than for the first design and that the insertion losses also decreased. The interaction between the field lines created by the conductors and the magnetic film was indeed favored in the second case. Finally, we show the tunability of the isolator with the polarizing field.

29 citations

Journal ArticleDOI
TL;DR: In this paper, a post deposition annealing is needed to obtain the crystallization of YIG films and the magnetic properties which are correlated with the magneto-optical properties.
Abstract: Thin films of Yttrium Iron Garnet (YIG) are grown by radio frequency magnetron non reactive sputtering system on quartz and Gadolinium Gallium Garnet (GGG) for optical applications or alumina substrates for microwave applications. A post deposition annealing is needed to obtain the crystallization of YIG films and the magnetic properties which are correlated with the magneto-optical properties. Their crystallographic, morphologic and magnetic properties are explored. The variation of Faraday rotation is studied versus the wavelength. For both optical substrates, quartz and GGG, results are comparable with the literature for bulk material. A microwave isolator was realized with YIG thin film on alumina substrate in a coplanar configuration. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

24 citations

Journal ArticleDOI
TL;DR: In this article, the authors used the interesting properties of magnetic thin films in order to improve planar inductors characteristics, and the results were obtained from simulations (Ansoft HFSS) for frequencies up to 5 GHz.

15 citations

Journal ArticleDOI
TL;DR: In this article, the authors present the experimental results of a coplanar isolator made on both bulk YIG and thin-film YIG, and observe the amplitude of the non-reciprocal effect, which is between 1.8 and 6.2 dB.
Abstract: In this paper, we present the experimental results of a coplanar isolator made on both bulk YIG and thin-film YIG. An external field has been applied on this device and we observe the amplitude of the nonreciprocal effect, which is between 1.8 and 6.2 dB for a resonance frequency of 3.3 and 6.9 GHz for bulk YIG and a nonreciprocal effect of 0.3 dB at 9 GHz for 2.5-μm YIG thin films. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 42: 470–471, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20339

9 citations


Cited by
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Journal ArticleDOI
TL;DR: Growth of nm-thick yttrium iron garnet films and ferromagnetic resonance (FMR) linewidth properties in the films were reported in this article, where films were grown on gadolinium gallium garnet substrates by pulsed laser deposition (PLD).
Abstract: Growth of nm-thick yttrium iron garnet films and ferromagnetic resonance (FMR) linewidth properties in the films are reported. The films were grown on gadolinium gallium garnet substrates by pulsed laser deposition (PLD). Films in the 5–35 nm thickness range showed a (111) orientation and a surface roughness between 0.1 and 0.3 nm. The 10 nm films showed a 10 GHz FMR linewidth of about 6 Oe and a damping constant of 3.2 × 10−4. The FMR linewidth increases with both the surface roughness and the surface Fe deficiency. Thicker films exhibit a smaller FMR linewidth and a lower damping constant.

261 citations

Journal ArticleDOI
TL;DR: In this paper, a reverse microemulsion technique with a combination of (NH4)2CO3 and NH3·H2O as precipitator was used to synthesize barium ferrite nanoparticles with uniform flaky structure.
Abstract: BaFe12O19 hexaferrite nanoparticles, containing cetyltrimethylammonium chloride (CTAC), n-hexanol, and cyclohexane, were synthesized by a reverse microemulsion technique with a combination of (NH4)2CO3 and NH3·H2O as precipitator. Barium ferrite nanoparticles with 30 nm diameter and uniform flaky structure were proved to be single magnetic domains, which have magnetic properties comparable to some of the best ever reported for fine barium ferrite powders by chemical methods. Heat-treatment conditions can significantly influence the formation of pure BaFe12O19 hexaferrite phase, where quenching and nonprecalcination would produce intermediates of α-Fe2O3 and BaFe2O4, as detected by X-ray diffraction (XRD) and Fourier transform infrared (FT-IR) analyses, resulting in lower magnetic properties. High magnetocrystalline anisotropy constant K and energy barrier EA calculated from Stoner−Wohlfarth theory may also account for the high coercivity for pure BaFe12O19. The variation of electrical conductivity during ...

181 citations

Journal ArticleDOI
TL;DR: In this paper, the results of spin wave propagation in distributed magnetic periodic structures, lumped systems, coupled waveguide structures, and controllable magnonic structures are discussed, and possibilities for further developing this circuitry are explored.
Abstract: Recent results in magnonics – a topical and rapidly developing branch of spintronics and magnetoelectronics – are presented. The paper describes measurement techniques and theoretical approaches used to explore physical processes associated with the spin-wave propagation in complex nano- and micro-dimensional magnetic structures. The results of the application of magnetic structures in signal processing and transmission systems are discussed. In particular, results on spin wave propagation in distributed magnetic periodic structures, lumped systems, coupled waveguide structures, and controllable magnonic structures are considered. Specific examples of circuitry based on magnonic structures are discussed, and possibilities for further developing this circuitry are explored.

176 citations

Journal ArticleDOI
TL;DR: In this article, the growth of nm-thick yttrium iron garnet (YIG) films by sputtering and ferromagnetic resonance (FMR) properties in the films were studied.
Abstract: Growth of nm-thick yttrium iron garnet (YIG) films by sputtering and ferromagnetic resonance (FMR) properties in the films were studied. The FMR linewidth of the YIG film decreased as the film thickness was increased from several nanometers to about 100 nm. For films with very smooth surfaces, the linewidth increased linearly with frequency. In contrast, for films with big grains on the surface, the linewidth-frequency response was strongly nonlinear. Films in the 7–26 nm thickness range showed a surface roughness between 0.1 nm and 0.4 nm, a 9.48-GHz FMR linewidth in the 6–10 Oe range, and a damping constant of about 0.001.

157 citations

Journal ArticleDOI
TL;DR: In this paper, a series of Co−Ti-doped barium-ferrite nanoparticles [Ba(CoTi)xFe12−2xO19, 0.25 ≤ x ≤ 1.0] were also prepared by this method.
Abstract: Barium ferrite (BaFe12O19) nanoparticles have been successfully synthesized from solvothermal route with the assistance of surfactant P123 (EO20PO70EO20), which has been proven to be a better method for barium-ferrite synthesis as compared to conventional hydrothermal technique, and the resultant product shows high-purity crystalline phase, small particle size, excellent magnetic properties, and characteristic of single magnetic domains. A series of Co−Ti-doped barium-ferrite nanoparticles [Ba(CoTi)xFe12−2xO19, 0.25 ≤ x ≤ 1.0] were also prepared by this method, indicating that this route is versatile for barium-ferrite nanoparticles with different chemical compositions. With increasing heteroatoms content, saturation magnetization and coercivity drastically decreased because of the selective substitution of Fe3+ sites by Co2+ and Ti4+ in the magnetoplumbite structure. By supplying these inorganic nanoparticles as nucleation sites, polyaniline/ferrite composites were prepared through in situ polymerization...

102 citations