Effects of Disorder on the Performance of Magnesium Diboride Microwave Resonators

• Published in: IEEE transactions on applied superconductivity Vol. 17; no. 2; pp. 3644 - 3647
• Main Authors: Ghigo, G., Andreone, D., Gerbaldo, R., Gozzelino, L., Laviano, F., Lopardo, G., Minetti, B., Monticone, E., Ummarino, G.A., Mezzetti, E.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: New York, NY IEEE 01.06.2007; Institute of Electrical and Electronics Engineers; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Aging; Applied sciences; Capacitors. Resistors. Filters; Circuit properties; Coplanar waveguides; Disorders; Electric, optical and optoelectronic circuits; Electrical engineering. Electrical power engineering; Electromagnetic scattering; Electromagnetic waveguides; Electronic equipment and fabrication. Passive components, printed wiring boards, connectics; Electronics; Exact sciences and technology; Gold; Ion radiation effects; Magnesium; Magnesium compounds; Mathematical models; Microwave circuits, microwave integrated circuits, microwave transmission lines, submillimeter wave circuits; Microwaves; Phenomenology; Resonators; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices; Superconducting devices; Superconducting films; Superconducting microwave devices; Superconductivity; Surface resistance; Temperature; Various equipment and components; Performance evaluation; Temperature dependence; Electromagnetism; Disordered system; Surface resistance; Input signal; Ageing; Polycrystal; Superconducting microwave devices; Grain boundary; Superconducting films; ion radiation effects; Radiation effect; Irradiation; Coplanar waveguides; Microwave resonator; Resistor; High temperature superconductor; Low temperature; Interband transition
• DOI: 10.1109/TASC.2007.899558
• ISSN: 1051-8223

A comprehensive understanding of the role of disorder in two-band superconducting magnesium diboride is an essential requirement for its use in potential applications. Within this framework, we investigated the role of disorder in modifying the performance of microwave coplanar resonators, characterized as a function of temperature and input power, before and after successive uniform irradiations with 250 MeV Au ions. Also sample aging has been considered as a further source of disorder. We show the main features of the peculiar phenomenology concerning the effects of disorder on the electromagnetic response of the resonator, due to surface resistance reduction at low-temperatures and to non-monotonic residual resistance as a function of disorder level. The analysis is mainly focused on the nonlinear response of the device. These results are discussed in the framework of the two-gap model with significant interband scattering, taking also into account the grain-boundary network underlying polycrystalline films.