Determination of coordinate dependence of a pinning potential from a microwave experiment with vortices

作者：Shklovskij V A^*; Dobrovolskiy O V

来源：Low Temperature Physics, 2013, 39(2): 120-124.

DOI：10.1063/1.4791773

The measurement of the complex impedance response accompanied by power absorption P(x) in the radiofrequency and microwave ranges represents a most popular experimental method for the investigation of pinning mechanisms and vortex dynamics in type-II superconductors. In the theory, the pinning potential (PP) well for a vortex must be a priori specified in order to subsequently analyze the measured data. We have theoretically solved the inverse problem at T - 0K and exemplify how the coordinate dependence of a PP can be determined from a set of experimental curves P(omega vertical bar j(0) ) measured at subcritical dc currents 0 %26lt; j(0) %26lt; j(c) under a small microwave excitation j(1) %26lt;%26lt; jc with frequency x. We furthermore elucidate how and why the depinning frequency omega(p), which separates the non-dissipative (quasi-adiabatic) and the dissipative (high-frequency) regimes of small vortex oscillations in the PP, is reduced with increasing j(0). The results can be directly applied to a wide range of conventional superconductors with a PP subjected to superimposed dc and small microwave ac currents at T %26lt;%26lt; T-c.

• 出版日期2013-2