Measuring the Lower Critical Field of Superconductors Using Nitrogen-Vacancy Centers in Diamond Optical Magnetometry
At a Glance
Section titled āAt a Glanceā| Metadata | Details |
|---|---|
| Publication Date | 2019-01-17 |
| Journal | Physical Review Applied |
| Authors | K R Joshi, N. M. Nusran, M.A. Tanatar, Kyuil Cho, Wayne R. Meier |
| Institutions | Ames National Laboratory, Iowa State University |
| Citations | 37 |
Abstract
Section titled āAbstractāThe lower critical magnetic field, $H_{c1}$, of superconductors is measured\nby using ensembles of NV-centers-in-diamond optical magnetometry. The technique\nis minimally invasive, and has sub-gauss field sensitivity and sub-$\mu$m\nspatial resolution, which allow for accurate detection of the vector field at\nwhich the vortices start penetrating the sample from the corners. Aided by the\nrevised calculations of the effective demagnetization factors of actual cuboid\n- shaped samples, $H_{c1}$ and the London penetration depth, $\lambda$, derived\nfrom $H_{c1}$ can be obtained. We apply this method to three well-studied\nsuperconductors: optimally doped Ba(Fe${1-x}$Co${x}$)$_2$As$_2$,\nstoichiometric CaKFe$_4$As$_4$, and high-$T_c$ cuprate\nYBa$_2$Cu$3$O${7-\delta}$. Our results are well compared with the values of\n$\lambda$ obtained using other techniques, thus adding another non-destructive\nand sensitive method to measure these important parameters of superconductors.\n