Numerical restoration of surface vortices in Nb films measured by a scanning SQUID microscope

29th International Symposium on Superconductivity

Ito, Atsuki^1 ; Huy, Ho Thanh^1,2 ; Dang, Vu The^1,2 ; Miyoshi, Hiroki^1 ; Hayashi, Masahiko^3 ; Ishida, Takekazu^1,4

Department of Physics and Electronics, Osaka Prefecture University, Sakai

599-8531, Japan^1

University of Sciences, Vietnam National University HCMC, Ho Chi Minh, Viet Nam^2

Faculty of Education and Human Studies, Akita University, Akita

010-8502, Japan^3

Institute for Nanofabrication Research, Osaka Prefecture University, Sakai

599-8531, Japan^4

关键词: Biot-Savart law;    Fourier transformations;    Magnetic distributions;    Scanning microscope;    Scanning SQUID microscope;    Spatial resolution;    Surface vortices;    Vortex profiles;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/871/1/012021/pdf
DOI  :  10.1088/1742-6596/871/1/012021

来源: IOP

【 摘 要 】

In the present work, we investigated a vortex profile appeared on a pure Nb film (500 nm in thickness, 10 mm x 10 mm) by using a scanning SQUID microscope. We found that the local magnetic distribution thus observed is broadened compared to a true vortex profile in the superconducting film. We therefore applied the numerical method to improve a spatial resolution of the scanning SQUID microscope. The method is based on the inverse Biot-Savart law and the Fourier transformation to recover a real-space image. We found that the numerical analyses give a smaller vortex than the raw vortex profile observed by the scanning microscope.