Multi-vortex versus interstitial vortices scenario in superconducting antidot arrays

• Published in: Physica. C, Superconductivity Vol. 470; no. 20; pp. 1112 - 1114
• Main Authors: Thakur, A.D., Ooi, S., Chockalingam, S.P., Jesudasan, John, Raychaudhuri, P., Hirata, K.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Amsterdam Elsevier B.V 01.11.2010; Elsevier
• Subjects: Antidot array; Antidots; Arrays; Columnar pinning sites; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Exact sciences and technology; Fluid flow; Interstitials; Lattices; Low tc films; Matching; Matching effect; NbN; Physics; Properties of type I and type II superconductors; Superconducting film; Superconducting films and low-dimensional structures; Superconductivity; Vortex lattices ,flux pinning, flux creep; Vortices; Antidot array; Columnar pinning sites; NbN; Superconducting film; Matching effect; Superconducting thin films; Patterning; Commensurate phases; Flux flow; Penetration depth; Thin films; Coherence length; Flux pinning; Vortices
• ISSN: 0921-4534; 1873-2143
• DOI: 10.1016/j.physc.2010.05.050

In superconducting thin films, engineered lattice of antidots (holes) act as an array of columnar pinning sites for the vortices and thus lead to vortex matching phenomena at commensurate fields guided by the lattice spacing. The strength and nature of vortex pinning is determined by the geometrical characteristics of the antidot lattice (such as the lattice spacing a0, antidot diameter d, lattice symmetry, and orientation) along with the characteristic length scales of the superconducting thin films, viz., the coherence length (ξ) and the penetration depth (λ). There are at least two competing scenarios: (i) multiple vortices sit on each of the antidots at a higher matching period and (ii) there is nucleation of vortices at the interstitial sites at higher matching periods. Furthermore, it is also possible for the nucleated interstitial vortices to reorder under suitable conditions. We present our experimental results on NbN antidot arrays in the light of the above scenarios.