Temperature dependence of vortex configuration by honeycomb hole arrays in a superconducting Nb film

Abstract

Determination of T c , vortex creation and vortex imaging of a superconducting Nb film using low-temperature magnetic force microscopy A honeycomb array of submicrometer holes in a Nb superconducting thin film has been fabricated to investigate the flux pinning effect. It is found that the minima positions reveal two regimes characterized by the matching fields and the fractional ones. It is believed that the complex behavior may come from more than one vortex being captured per pinning site. Furthermore, the temperature dependence of the saturation number of vortices per pinning site together with vortex-vortex interaction gives the complex vortex configurations.

Vortex molecular crystal and vortex plastic crystal states in honeycomb and kagomé pinning arrays

“…2 is very similar to the experimental results observed for honeycomb arrays in Ref. [33]. In the experiments, strong commensuration effects appeared at B/B that the commensuration effects at B/B H φ = 3 and 4 are very weak or absent while those at B/B H φ = 3.5 and 4.5 are very pronounced.…”

“…In Ref. [33], it was also observed that for fields greater than the second matching field, B/B φ > 2, the commensuration effects at half-integer matching fields become more prominent than those at integer matching fields. This effect can be understood by considering that since the honeycomb pinning array is simply a triangular pinning array that has been diluted by 1/3, the field B/B φ = 1.5 for the honeycomb array would correspond to an integer matching field B/B φ = 1 in a triangular array of the same density.…”

“…In Ref. [33], several unusual features were observed, including pronounced matching effects of equal magnitude at magnetic fields corresponding to both integer and half integer multiples of the matching field for vortex densities up to to the fifth matching field B/B φ = 5. This result is in contrast to the response of square or triangular pinning arrays, where commensuration effects are much weaker at nonmatching fields than at integer matching fields.…”

“…Only a single experimental study [33] has been performed on honeycomb pinning arrays to our knowledge. In Ref.…”

Vortex interaction enhanced saturation number and caging effect in a superconducting film with a honeycomb array of nanoscale holes

“…For example, extensive molecular dynamics simulations have been conducted in recent years 21 , which revealed remarkable variety of static and dynamic phenomena at integer and noninteger fillings. Experimental studies have also been performed recently, showing unusual features of such superconducting systems such as guided vortex motion [25][26][27][28] . In combination with computer simulations, we reveal that interstitial vortices appear once the saturation number n si predicted for an isolated defect is exceeded.…”