Flux Pinning by the InAs Nanorods in Nb Thin Films

We investigate the feasibility of using the semiconductor InAs nanorods for flux pinning in Nb thin films. The InAs nanorods are grown in the vertical direction on Si (111) substrates by metal-organic chemical vapor deposition. The grown nanorods are about 80 nm in diameter, 5 μm in height, and 2 × 10
⁹
/cm
²
in density. The four-terminal strip pattern of Nb films is fabricated on nanorod-grown substrates and, for the reference, on nanorod-free substrates by sputtering through a metal mask. We observe clear enhancement of the upper critical fields and the critical current densities for field oriented along the nanorod axis in the Nb film with embedded nanorods. We also confirm the flux pinning by InAs nanorods in the measurements of the angular dependence of critical current densities. Our results indicate that the InAs nanorods are promising linear defects for flux pinning research in superconductors.