Direct-current-assisted microwave quenching of YBa2Cu3O7−δ coplanar waveguide to a highly dissipative state

Abstract

The paper reports on finding the effect of a strong change in the microwave losses in an HTSbased coplanar waveguide (CPW) at certain values of the input power P in and direct current I dc .CPW on the basis of 150 nm thick YBa 2 Cu 3 O 7-δ epitaxial film on a single crystal MgO substrate was studied experimentally. A sharp and reversible transition of the CPW into a strongly dissipative state at the certain meanings of P in and I dc depending on temperature was observed.Apparently the effect can be explained by self-heating of HTS structure caused by magnetic flux flow under the joint influence of MW and DC.Since discovery of high-temperature superconductors (HTS) in 1986 [1] a lot of attention has been given to studying nonlinear properties of HTS in microwave (MW) fields [2][3][4].

To the Phenomenological theory of Avalanche-Like Effect in Dc-Biased Microwave Nonlinear HTS Transmission Line

“…But the results of our studies (see Fig. 3 in work [5]) do not agree with this formula in the general case. In particular, at temperatures close to the critical one, the value of IL may decrease with the growth of in , what is not allowed in relation (4).…”

“…The dependences of microwave losses = = 10 lg( out / in ) on the temperature were experimentally studied for various values of the input microwave power in and the magnitudes of the direct current through a waveguide. Typical relevant dependences measured in the presence and absence of the direct current can be found in work [5].…”

“…When experimentally studying the properties of a microwave transmission line of the coplanar waveguide (CPW) type based on HTSCs, strong (jumplike) changes in microwave power losses were revealed at certain values of input power in , dc current dc , and waveguide temperature < c , where c is the critical temperature [5,6]. In this connection, a number of works should be mentioned, in which the transition of microwave HTSC-based structures into the dissipative state also occurred at certain values of a direct current, and the microwave signal was intentionally weak, being used only to control a state of the HTSC structure (see, e.g., work [7]).…”

“…In principle, those effects may make it possible to create of high-precision microwave power, temperature, and dc sensors on the basis of microwave HTSC-based transmission lines, in particular, CPWs. Figure 1 illustrates the schematic diagram of the CPW cross-section [5]. The CPW was fabricated (THEVA, Germany) using the photolithographic method on the basis of an epitaxial HTSC film YBa…”

Upper Frequency Limits for Vortex Guiding and Ratchet Effects

“…The microwave signal was generated and analyzed by an Agilent E5071C vector network analyzer (VNA). To present the vortex-related microwave loss, in what follows we use the notation of insertion loss, IL, deduced by the standard relation IL ≡ −S 21 (f, P, H)/S 21 (f, P, H ref ) [16,28,30,32,46], where S 21 (f, P, H ref ) is the frequencyand microwave-power-dependent reference loss at H ref > H c2 . Figure 2 displays the vortex-related microwave loss with increase of the dc current of positive polarity at H = 20 mT and four ac frequencies.…”