Vortex depinning from large isolated pin

The pin-breaking force to detach a vortex from a single large pin is the key parameter in strong-pinning theory. Depinning is nontrivial process controlled by instability of critical configuration. We studied the pin-breaking process for spherical and ellipsoidal particles. These animations illustrate depinning of isolated vortex from large-size (diameter a = 16ξ) and small-size (a = 4ξ) spherical particles.

Depinning from large particle.

Depinning from small particle.

Left plot illustrates the size dependence of the pin-breaking force from spherical particles. Right figure shows vortex critical configuration in the vicinity of particle for particles with different size (symbols mark vortex lines).