Description:

Dr. Ivan Sadovsky, Fermilab

Title: Targeted evolution of pinning configuration for lower energy dissipation in superconductors

Abstract:

Understanding the dynamic behavior of vortex matter in type-II superconductors remains a major challenge. On the fundamental side, an interplay of fluctuations, vortex interactions and disorder lead to a wealth of nontrivial correlated behaviors. For applications, the major problem is impeding vortex motion by introducing structural defects in order to suppress the related energy dissipation. The effect of structural defects is, however, two-fold: while arresting vortices in a bulk, defects damage the surface barrier promoting vortex entrance across into the superconductor. The task is thus the optimizing pinning landscape to achieve the best performance.

We use large-scale simulations of the time-dependent Ginzburg-Landau equation that harnesses vortex-vortex and vortex-defect interactions [1]. The obtained results show excellent quantitative agreement with experimental data [2]. The recent progress in advanced computing enabled us to put forth a new paradigm: the simulation-assisted design of defect structures having predictive capabilities [3]. In the framework of this paradigm the usual Edisonian trial-and-error method is replaced by the material engineering of (i) current-carrying capability of superconducting wires, (ii) quality factor and acceleration field of superconducting radio frequency cavities, and (iii) magnets for X-ray undulators.

In this study we present a targeted evolution approach [4], capable to predict the optimal defect morphology and concentration to ensure the best superconductor properties. In this method, the position, size, and shape of each defect are varied individually resulting in optimal configuration of defects without specific assumptions about their type and shape.

[1] Sadovskyy, et al., J. Comp. Phys. 294, 639 (2015).
[2] Sadovskyy, et al., Phys. Rev. Applied 5, 014011 (2016).
[3] Sadovskyy, et al., Adv. Mat. 28, 4593 (2016).
[4] Sadovskyy, et al., submitted (2018).

Host: J. A. Sauls