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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 (BaFe 12 O 19 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 m thick, were deposited under optimized conditions by radio frequency magnetron sputtering on alumina substrates. The films were crystallized using a 800 C 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 m 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 m 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.

PACS 78.20.Ls, 85.70.Sq 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.

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PACS 75.50.Gg, 75.60Nt, 75.70Ak Ferrites have magnetic properties suitable for electronic applications, especially in the microwave range (circulators and isolators). Hexagonal ferrite, such as barium ferrite, are of great interest for microwave device applications because of their large resistivity and high permeability at high frequencies. BaM films are deposited under optimized conditions by RF magnetron sputtering on alumina substrates. In order to crystallize the films that are amorphous after deposition, a post deposition annealing at 800 °C is implemented. All samples present a good crystallization, a smooth surface and a good in-depth uniformity. The magnetic properties of BaM films show an optimized coercive force and saturation magnetization of 330 kA/m and 500 mT respectively. These values are close to that of the bulk BaM. Isolators are then realized and measured by a vector network analyzer and a probing system. Results on transmission coefficients show a non reciprocal effect, which reaches 8.3 dB/cm at 50 GHz. This proves that such a component behaves like an isolator in the 50 GHz band.

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In order to miniaturize a microwavte passive