Showing papers by "J. Albino Aguiar published in 2011"
TL;DR: In this paper, the authors investigated the dynamics of the annihilation of a vortex-antivortex pair in a superconducting mesoscopic prism of square transversal section with a square antidot inserted at its center.
Abstract: In this work, we investigated theoretically the dynamics of the annihilation of a vortex–antivortex pair in a superconducting mesoscopic prism of square transversal section with a square antidot inserted at its center. The sample is immersed in a magnetic field applied perpendicular to the sample plane. It is assumed that the inner hole is made of a material whose properties are accounted on de Gennes boundary conditions via de Gennes extrapolation length (b parameter). We analyze the nucleation of vortices and antivortices by increasing the magnetic field from zero until the first vortex is created and then reversing the polarity of the applied magnetic field until an antivortex is also created. Depending on the b parameter, the vortex–antivortex encounter can take place at the hole or at the superconducting region around it. In the framework of the time dependent Ginzburg–Landau theory, we calculate the magnetization, order parameter topology, the position and the velocity of the vortex and antivortex singularities as a function of time.
11 citations
TL;DR: In this article, the vortex dynamics in a superconducting film with nano-engineered open vortex traps are investigated, and the design is based on the confinement of the vortex motion within two repulsive walls, one with periodic microprotrusions and the other one smooth.
Abstract: We investigate experimentally and theoretically the vortex dynamics in a superconducting film with nanoengineered open vortex traps which provide tunable pinning, ranging from no pinning for a certain current direction to finite pinning when reversing the current flow. The design is based on the confinement of the vortex motion within two repulsive walls, one with periodic microprotrusions and the other one smooth. Clear commensurability effects are seen if the bias current drives the vortices inside the traps, whereas these effects are much less pronounced when the current pushes the vortices against the smooth surface. For small periods of the protrusions or large vortex sizes, the properties displayed by the vortices, pushed against these two surfaces of dissimilar roughness can be thought of as due to the change of effective sliding friction.
4 citations