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The specially designed and built UHV bakeable water cooled plasma jet system with DC hollow cathode discharge enables to run either one or two straight jets or one pair of convergent jets. The apparatus achieved demanded vacuum parameters, i.e. both UHV conditions before the deposition and possibility to adjust the chosen Q-pB points. Layers of pure iron, cobalt, AlN and finally FeCo-AlN magnetic nitride nanocomposite films with GHz applications were prepared. Plasma deposition process was performed by reactive sputtering of combined Fe50Co50+Al nozzle in Ar + N2 working gas mixture flow (total pressure 0.15 Pa, partial N2 pressure 0.35%) on water-cooled (at 15°C) Si, SiO2(200nm)/Si and glass substrates. Magnetic anisotropy of films was induced by applied external magnetic field during the deposition. The investigated films have thickness about 600 nm and the approximate composition Fe40Co40Al10N10. X-ray diffraction and chemical analysis revealed that the films consist of nanocrystalline Fe-Co grains with the size of about 10 nm and dispersed amorphous AlN clusters. Mössbauer spectra were obtained using a conversion electrons Mössbauer spectrometry with a 57Co/Rh source. The Mössbauer spectra contain 5 sextets. Analyses were additionally complemented by the study of nuclear magnetic resonance and HRTEM. Magnetic domain structure refinement in hard-axis fields and on the edge is typical for uniaxial thin films. These materials are magnetically soft with coercitivity about 2 Oe, with anisotropic field cca 20 Oe and saturation magnetization 16-19 kG (measured by AC hysteresis loop tracer). The resistivity is increased by the nitridation from original value ρ ~ 40-60 µΩcm up to 160-200 µΩcm, thus, the eddy currents are distinctively suppressed in the films at their use in the GHz mobile communication inductors. The high frequency dependence of permeability was investigated in the range of 0.1-2 GHz. The characteristic frequency at which the natural ferromagnetic resonance occured is about 1.7 GHz. Support by grants GA AV CR, IAA200100701 and KAN 400100653, is gratefully acknowledged.
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