Directional Vortex Pinning at Microwave Frequency in YBa2Cu3O7−x Thin Films with BaZrO3 Nanorods

Effective vortex pinning in MgB2 thin films

We discuss the pinning properties of MgB2 thin films grown by pulsed-laser deposition (PLD) and by electron-beam (EB) evaporation. Two mechanisms are identified that contribute most effectively to the pinning of vortices in randomly oriented films. The EB process produces low defected crystallites with a small grain size providing enhanced pinning at grain boundaries without any degradation of ...

Images and nonlocal vortex pinning in thin superfluid films

For thin films of superfluid adsorbed on a disordered substrate, we derive within a mean field (Hartree) description of the condensate the equation of motion for a vortex in the presence of a random potential. The compressible nature of the condensate leads to an effective pinning potential experienced by the vortex which is nonlocal, with a long range tail that smoothes out the random potentia...

Modeling flux pinning in thin undoped and BazRo3-doped YBCO films

Magnetic force microscopy of vortex pinning at grain boundaries in superconducting thin films

We succeeded to image with magnetic force microscopy individual vortices in thin Nb films as well as in thin YBa2Cu3O7!d (YBCO) films. Relying on the imaging of microfabricated gold loops, we are able to identify the exact location of the vortices within 10 nm with respect to topographic features. The center of most of the vortices is located in between the grains appearing at the film surface....

Microwave vortex dynamics in Tl-2212 thin films

We present measurements of the effective surface impedance changes due to a static magnetic field, ∆Z(H, T ) = ∆R(H, T ) + i∆X(H, T ), in a Tl-2212 thin film with Tc > 103 K, grown on a CeO2 buffered sapphire substrate. Measurements were performed through a dielectric resonator operating at 47.7 GHz, for temperatures 60 K≤ T < Tc and magnetic fields ≤ 0.8 T. We observe exceptionally large field...