Vortices in dense self-assembled hole arrays.
We present a study of the upper critical field and pinning strength from the resistivity and magnetization of a Nb film containing a dense array of 45 nm diameter holes on a hexagonal lattice with a spacing of 101 nm. The holes were formed by self-assembly in anodic aluminum oxide (AAO) using an electrochemical procedure. Confinement effects and Little-Parks oscillations are seen above 6 K, and strong pinning with matching field effects is seen below 6 K. Above the first matching field interstitial vortices coexist with vortices trapped in the hole array. Pinning in the Nb films with hole arrays is enhanced by two orders of magnitude over that in continuous Nb films. At low temperature, flux avalanches are observed and imaged using the magneto-optical Faraday effect.
- Research Organization:
- Argonne National Lab., IL (US)
- Sponsoring Organization:
- US Department of Energy (US)
- DOE Contract Number:
- W-31109-ENG-38
- OSTI ID:
- 803879
- Report Number(s):
- ANL/MSD/CP-108830
- Country of Publication:
- United States
- Language:
- English
Similar Records
Superconducting transition and vortex pinning in Nb films patterned with nano-scale hole-arrays.
Pinning, flux diodes and ratchets for vortices interacting with conformal pinning arrays