Vortex–antivortex annihilation in underdoped YBa2Cu3O6.354

Locally applied magnetic fields can be used to create vortex–antivortex pairs in superconducting films and thin crystals. These pairs typically annihilate on some timescale which depends on temperature. We use a 21 μm diameter field coil integrated onto a scanning superconducting quantum interference device to create and observe vortex–antivortex pairs. We present measurements of the distribution of annihilation times as a function of temperature, which should allow us to determine the pinning forces for vortices in these highly underdoped samples of YBa2Cu3O6.354. [Copyright &y& Elsevier]