(1) Instituto de Física, Universidade Federal do Rio de Janeiro, C.P. 68528, 21941-972 Rio de Janeiro RJ, Brazil;(2) Instituto de Física, Pontifícia Universidade Católica do Rio de Janeiro, C.P. 38071, 22452-970 Rio de Janeiro RJ, Brazil
Abstract:
A vortex line is shaped by a zigzag of pinning centers and we study here how far the stretched vortex line is able to follow
this path. The pinning center is described by an insulating sphere of coherence length size such that in its surface the de
Gennes boundary condition applies. We calculate the free energy density of this system in the framework of the Ginzburg-Landau
theory and study the critical displacement beyond which the vortex line is detached from the pinning center.