Switching Response of $\hbox {YBa}_{2}\hbox {Cu}_{3} \hbox {O}_{7 - \delta }$ to Simultaneous Application of Near-Critical Current, Field, and Temperature

We injected a dc near-critical current through a yttrium-barium-copper oxide (YBCO) superconductor microbridge in the presence of a high pulsed ac magnetic field (10 MT/s up to 20 T) parallel to the dc current flow - the so-called Lorentz force free configuration. A transmitted RF signal probed the YBCO mixed state that followed the ac magnetic field cycles. Based on inflection points on this modulated RF signal, we found where the YBCO switched from a superconducting to normal (S-N) state. Injecting a dc near-critical current does not affect the S-N switch time or the S-N field point, at least 2° below the critical temperature, i.e., T_c. Rather, the injected dc current only suppresses the RF signal´s magnitude across its duration. At 5° below Tc, injecting a current does modify the S-N transition point and shorten the switch time. Applications for cryotron-like switches in superconducting magnetic energy storage devices are discussed.