Incorporation of ferromagnetic metallic films in planar transmission lines for microwave device applications

• Published in: IEEE transactions on magnetics Vol. 37; no. 4; pp. 2392 - 2394
• Main Authors: Cramer, N., Lucic, D., Walker, D.K., Camley, R.E., Celinski, Z.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: New York, NY IEEE 01.07.2001; Institute of Electrical and Electronics Engineers; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Applied sciences; Attenuation; Coplanar waveguides; Devices; Electronics; Exact sciences and technology; Iron; Magnetic device characterization, design, and modeling; Magnetic devices; Magnetic fields; Magnetic films; Magnetic resonance; Magnetic separation; Magnetism; Microstrip; Microwave devices; Microwaves; Noise levels; Permalloy; Resonant frequency; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices; Ferromagnetic resonance; Microwave device; Coplanar technology; Theoretical study; Ferromagnetic materials; Microwave; Coplanar waveguides; Waveguide; Magnetic thin films; Thin film
• DOI: 10.1109/20.951182
• ISSN: 0018-9464

We constructed a series of microstrip and coplanar microwave waveguides. These structures use metallic ferromagnets and therefore exhibit strongly frequency-dependent attenuation and phase-shift effects. The lines have maximum attenuation peaks occurring at the ferromagnetic resonance frequency, which increases with applied magnetic field. Such properties are used in band-stop filters. The devices used monocrystalline Fe films grown by molecular beam epitaxy and polycrystalline sputtered permalloy films. For our devices that incorporated Fe the band-stop frequencies ranged from 10-20 GHz for applied fields up to only 80 kA/m (1000 Oersted). For devices using permalloy, the band-stop frequency was in the 5-10 GHz range for applied fields less than 80 kA/m. The maximum power attenuation was about 100 dB/cm, much larger than the previously reported values of 4 dB/cm. The resonance condition also affects the phase of the transmitted wave, strongly changing phase above and below the resonance frequency. The result is a phase-shifter that is tunable with applied magnetic field. We observed phase changes of over 360/spl deg//cm with an applied field of less than 40 kA/m.