Interface crack between superconducting film and substrate

Abstract

The interface crack problem in the superconducting film-substrate structure under the magnetic field is investigated. A solution of the two-dimensional magnetoelastic problem is found. It is assumed that the plane stress state of deformation prevails in the structure. We take into consideration both cases of interface crack in the film-substrate structure and the superconductor slab. The fracture behaviors are considered for the non-superconducting substrate and superconducting substrate. Based on the simple geometrical and material assumptions, we express the explicit analytical description of the stress intensity factor and energy release rate. An increase of the stress intensity factor and energy release rate with the applied field has been observed. During the field reduction, the variations of the fracture behavior exhibit a complex characteristic. In addition, the effect of the deformation of the substrate is significant. This work may provide a tool for the analysis of the mechanical instability in the film-substrate structure.

Crack Problem for Thin Superconducting Strip in a Perpendicular Magnetic Field

“…Thus, we only consider the field descent process in which cracking may occur. It is to be noted that, for the interface crack between the substrate and the film, compressive stress can also lead to cracking [20]. Based on the separate analysis of the elasticity problem, we can obtain quantitative fracture behavior for the central crack.…”

Fracture behaviors of thin superconducting films with field-dependent critical current density

“…In recent years, many theoretical analyses for the crack problem of long rectangular slabs and long cylinders under electromagnetic force have been achieved [11][12][13]. Very recently, the central crack and interface crack problem of a thin superconducting strip were investigated by a field-independent c J (the Bean model) [14,15].…”