Study of Energy Dissipation in the Mixed-State YBa2Cu3O7-δ Superconductor with Partially Deoxygenated Structures

Abstract

Energy dissipation from vortex motion, which appears as a resistivity of the mixed-state superconductor, limits the range of type II superconductors in low- and high-power electronics and optoelectronics. The level of dissipation increases with the development of the vortex motion phase from that of the thermally activated flux flow to that of the flux creep and finally to that of the flux flow. The vortex motion regimes depend on the balance between bias current-self-produced Lorentz force, accelerating vortices, and the pinning force, which, together with a magnetic drag force from pinned vortices, tends to stop the vortex motion. The current paper reports on energy dissipation in YBa2Cu3O7-δ (YBCO) devices provided with partially deoxygenated structures mutually interacting by magnetic force with one another. The shape of the structure and the magnetic interaction between the trapped and moving vortices, as well as the magnetic interaction between neighboring structures, can cause the appearance of voltage steps in the device’s current–voltage characteristics observed in temperature range 0.94 ≥ T/Tc ≥ 0.98 (here, Tc = 91.4 K is the temperature of the superconducting transition in the YBCO material). Current findings demonstrate the potential of artificial structures to control vortex motion in a mixed-state YBCO superconductor by means of a temperature, bias current, and a specific configuration of the structure itself and a profile of the oxygen distribution in it.

Superconducting and Mechanical Properties of the Tl0.8Hg0.2Ba2Ca2Cu3O9−δ Superconductor Phase Substituted by Lanthanum and Samarium Fluorides

“…The nonlinear segment of the curve shows a voltage drop occurring at a specific applied current value (I c ), described by flux creep (Lorentz force FL = Pinning force FP). The final portion of the curve demonstrates an increase in the linear trend, resulting from vortex pair unbinding induced by a strong Lorentz force (FL > FP), explained through flux flow theories [38]. Various factors, including porosity, crystal structure, oxygen deficiency, grain morphology, relative volume fraction, and the presence of different elements, can influence both J c and T c .…”