Vortex Dynamics in Type II SuperconductorsYuri V. Artemov Ph.D. Student in PhysicsMentor: Brian B. Schwartz Professor of PhysicsCUNY Fall 1998

OverviewProperties of superconductorsTwo types of superconductorsTheories of superconductivityVortices in type II superconductorsInteraction between vorticesInteraction with defectsVortex dynamicsProposed researchVortices and computersSummary

Properties of Superconductors

Two Types of SuperconductorsMagnetizationMagnetic FieldCritical Field

Theories of SuperconductivityLondon EquationBCS TheoryGinzburg-Landau TheoryElectrons can attract via phononsAttraction leads to energy gap 1.76Tcisotope effect

Vortices in Type II SuperconductorsMagnetic FieldCurrent

Interaction between VorticesLorenz type forceRepulsionTriangular lattice

Interaction with DefectsFlux CreepActivation energy behaviorPinningVacancies, voids, inhomogeneities, where superconductivity is weakPinning decreases energy losses caused by flux creep

Vortex DynamicsCollective behaviorVortices interact stronglyEffects of disorderInteraction with pinning centersMany degrees of freedom1012 vortices in a sampleThreshold dynamicsCan be driven to marginally stable state

Proposed ResearchStudy the dynamics of vortices in type II superconductorsGiven a superconductor with a certain pinning landscape, how do vortices move inside it?How do microscopic pinning parameters affect measured macroscopic quantities?How do vortices start moving when slowly driven towards the threshold of instability?How to characterize dynamical instabilities in a superconductor?

Vortices and ComputersVortices can be studied using computer simulationsA powerful theoretical tool to answer questions raised aboveAllows to study phenomena hard to observe experimentallyVortices can be effectively visualized using modern 3D design softwareMaking them more understandable to non-physics audienceTools to be usedPowerful workstations at the CUNY New Media LabSoftimage 3D softwareDirectX technology with Visual C++ and Visual BasicMatlab, MathematicaJava & WWW

SummaryGeneral properties of superconductorsType I and type II superconductorsTheories of superconductivityVortices in type II superconductorsVortex interactions and dynamicsProposed researchUsing computers to study and visualize vortices

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