Vortex distributions near surface steps observed by scanning SQUID microscopy

B. L. T. Plourde; D. J. Van Harlingen; N. Saha; R. Besseling; M. B. S. Hesselberth; P. H. Kes

doi:10.1103/PhysRevB.66.054529

← Back to search

Vortex distributions near surface steps observed by scanning SQUID microscopy

B. L. T. Plourde, D. J. Van Harlingen, N. Saha, R. Besseling, M. B. S. Hesselberth, P. H. Kes

DOI 10.1103/PhysRevB.66.054529 · Physical Review B

T1

Active bibliographic source — not scientific approval

Bibliographic access preserves source history; it does not approve extracted materials or validate reported claims. Review warnings on each occurrence separately.

Abstract

We have used a scanning superconducting quantum interference device microscope to image individual vortices near lithographically patterned surface steps in weak-pinning superconducting thin films of amorphous MoGe. The field-cooled vortex distributions are strongly influenced by the surface steps, with an enhanced vortex density along the thin side of the steps and a wide vortex-free region along the thick side of the steps. The surface steps induce orientational order that persists for many intervortex spacings away from the steps. We study the effects of surface step pinning for different magnetic-field strengths and step heights by analyzing the intervortex spacing and computing vortex correlation functions. For certain sample configurations, we are able to apply a Lorentz force to the vortices and observe an asymmetric vortex response near the surface steps. We discuss the interaction between a vortex and a surface step and consider possible mechanisms for generating the vortex distributions which we observe upon field cooling.

Source-reported materials — not catalogue approval

Formula	Reported Tc (K)	Pressure (GPa)	Type
MoGe Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	6.5	Pressure not reported	unknown