Nonlinear Dielectric Microwave Losses in MgO Substrates

M. A. Hein; D. E. Oates; P. J. Hirst; R. G. Humphreys; A. V. Velichko

doi:10.1063/1.1447000

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Nonlinear Dielectric Microwave Losses in MgO Substrates

M. A. Hein·D. E. Oates·P. J. Hirst·R. G. Humphreys·A. V. Velichko

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Abstract

We have investigated the nonlinear surface impedance and two-tone intermodulation distortion of nine epitaxial YBa2Cu3O7-d films on MgO substrates, using stripline resonators, at frequencies f=2.3-11.2GHz and temperatures T=1.7K-Tc. The power dissipation decreased by up to one order of magnitude as the microwave electric field was increased to about 100V/m for T<20 K, while the reactance Xs showed only a weak increase. The minimum of the losses correlated with a plateau in the intermodulation signal. The same features were observed for a Nb film on MgO. The anomalous response is due to nonlinear dielectric losses in the substrate, which can be described by defect dipole relaxation.

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M. A. Hein, D. E. Oates, P. J. Hirst, R. G. Humphreys, A. V. Velichko. 2002-01-22. Nonlinear Dielectric Microwave Losses in MgO Substrates. https://doi.org/10.1063/1.1447000

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