Microwave intermodulation distortion of MgB2 thin films

Abstract

The two tone intermodulation arising in MgB2 thin films deposited in-situ by planar magnetron sputtering on sapphire substrates is studied. Samples are characterised using an open-ended dielectric puck resonator operating at 8.8 GHz. The experimental results show that the third order products increase with the two-tone input power with a slope ranging between 1.5 and 2.3. The behaviour can be understood introducing a mechanism of vortex penetration in grain boundaries as the most plausible source of non linearities in these films. This assumption is confirmed by the analysis of the field dependence of the surface resistance, that show a linear behaviour at all temperatures under test.

13 pages, 3 figures; to be published in Appl. Phys. Lett

References in corpus (2)

• Super-conducting critical fields and anisotropy of a MgB2 single crystal
• High quality MgB2 thin films in-situ grown by dc magnetron sputtering

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• Effects of Weak Links in the Nonlinear Microwave Response of MgB2 Superconductor
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• Linear and nonlinear electrodynamic response of bulk CaC6 in the microwave regime