Nonlinear response of HTSC thin film microwave resonators in an applied DC magnetic field

Abstract

The non-linear microwave surface impedance, Zs = Rs + iXs, of patterned YBCO thin films, was measured using a suspended line resonator in the presence of a perpendicular DC magnetic field, HDC, of magnitude comparable to that of the microwave field, H rf . Signature of the virgin state was found to be absent even for relatively low microwave power levels. The microwave loss was initially found to decrease for small applied HDC before increasing again. Also, non-linearities inherent in the sample were found to be substantially suppressed at low powers at these applied fields. These two features together can lead to significant improvement in device performance.

Anomalous microwave response of high-temperature superconducting thin-film microstrip resonator in weak dc magnetic fields

“…surface resistance R s and (or) surface reactance X s change non-monotonically with applied mw or dc magnetic field, were observed [16][17][18][19]. Choudhury et al reported an anomalous field dependence of surface resistance R s of a YBCO suspended line resonator in the presence of a weak, perpendicular dc magnetic field at 10K.…”

Nonlinear dielectric microwave losses in MgO substrates

“…The sources of nonlinearities are not well understood at present, and several groups have reported unexpected features like the recovery of superconductivity [4][5][6][7][8] or non-cubic power dependences of the thirdorder two-tone intermodulation product (IMD) or harmonic generation [9,10].…”

Influence of magnetic impurities on the microwave resistance of overdopedYBa2Cu3OProkhorov1, Kaminsky2, Lee3 2001Phys. Rev. B1000View full textAdd to dashboardCite

“…20 It is worth noting that the magnetic recovery effect, connected with a decrease in the microwave absorption for a small dc magnetic field, has been already observed. 35 FIG. 3.…”