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Quantitative imaging of Abrikosov vortices by scanning quantum magnetometry

Clemens Schäfermeier, Ankit Sharma, Christopher Kelvin von Grundherr, Andrea Morales, Jan Rhensius, Gabriel Puebla-Hellmann, Mirko Bacani

TL;DR

The study addresses the challenge of quantitatively imaging Abrikosov vortices in type-II superconductors. It leverages cryogenic scanning nitrogen vacancy magnetometry (NVM) with cw-ODMR in a closed-cycle cryostat to map $B_z(x,y)$ at nanoscale resolution under field-cooling, without requiring on-sample microwave structures. In BSCCO-2212, a well-ordered triangular lattice is observed with lattice spacing and magnetic induction consistent with flux quantization, while a YBCO thin film shows a disordered vortex arrangement due to strong pinning, yet the measured vortex density matches the applied field. The work demonstrates a helium-free, quantitative tool for real-space vortex studies, with implications for probing vortex dynamics, pinning landscapes, and engineered superconducting heterostructures across varied temperatures and fields.

Abstract

Understanding vortex matter in type-II superconductors is central to controlling dissipation and flux pinning in superconducting materials and devices. Here, we use cryogenic scanning nitrogen vacancy magnetometry (NVM) to image Abrikosov vortices in the cuprate superconductors BSCCO-2212 and YBCO under controlled field-cooled conditions. Measurements, which are performed using continuous-wave optically detected magnetic resonance (cw-ODMR) in a closed-cycle cryostat, yield quantitative magnetic-field maps with nanoscale spatial resolution. In BSCCO-2212 at 71 K, we resolve a well-ordered triangular vortex lattice, whose symmetry and spacing are confirmed through 2D Fourier analysis and are consistent with flux quantization. YBCO thin films imaged at 3 K exhibit a more disordered vortex arrangement reflecting stronger pinning, while maintaining quantitative agreement between measured vortex density and the applied magnetic field. These results render our cryogenic scanning NVM a reliable quantitative tool for real-space studies of vortices in high-$T_c$ superconductors, in particular since such a remarkable magnetic resolution has been achieved within relatively short acquisition times of 2 to 4 h.

Quantitative imaging of Abrikosov vortices by scanning quantum magnetometry

TL;DR

The study addresses the challenge of quantitatively imaging Abrikosov vortices in type-II superconductors. It leverages cryogenic scanning nitrogen vacancy magnetometry (NVM) with cw-ODMR in a closed-cycle cryostat to map at nanoscale resolution under field-cooling, without requiring on-sample microwave structures. In BSCCO-2212, a well-ordered triangular lattice is observed with lattice spacing and magnetic induction consistent with flux quantization, while a YBCO thin film shows a disordered vortex arrangement due to strong pinning, yet the measured vortex density matches the applied field. The work demonstrates a helium-free, quantitative tool for real-space vortex studies, with implications for probing vortex dynamics, pinning landscapes, and engineered superconducting heterostructures across varied temperatures and fields.

Abstract

Understanding vortex matter in type-II superconductors is central to controlling dissipation and flux pinning in superconducting materials and devices. Here, we use cryogenic scanning nitrogen vacancy magnetometry (NVM) to image Abrikosov vortices in the cuprate superconductors BSCCO-2212 and YBCO under controlled field-cooled conditions. Measurements, which are performed using continuous-wave optically detected magnetic resonance (cw-ODMR) in a closed-cycle cryostat, yield quantitative magnetic-field maps with nanoscale spatial resolution. In BSCCO-2212 at 71 K, we resolve a well-ordered triangular vortex lattice, whose symmetry and spacing are confirmed through 2D Fourier analysis and are consistent with flux quantization. YBCO thin films imaged at 3 K exhibit a more disordered vortex arrangement reflecting stronger pinning, while maintaining quantitative agreement between measured vortex density and the applied magnetic field. These results render our cryogenic scanning NVM a reliable quantitative tool for real-space studies of vortices in high- superconductors, in particular since such a remarkable magnetic resolution has been achieved within relatively short acquisition times of 2 to 4 h.
Paper Structure (5 sections, 8 equations, 3 figures)

This paper contains 5 sections, 8 equations, 3 figures.

Table of Contents

  1. Introduction
  2. Theoretical Background
  3. Experimental Methods
  4. Results
  5. Conclusion

Figures (3)

  • Figure 1: Commercial cryogenic NV magnetometer (attoNVM). Schematic overview of the attoNVM microscope integrated into an attoDRY2200 closed cycle cryostat, providing a low vibration, cryogen-free environment for nanoscale magnetic imaging. Insets highlight the QZabre diamond probe mounted at the scanner apex, hosting a shallow NV center near the diamond tip apex and an integrated on-chip microwave line on the same carrier chip for efficient ODMR excitation at cryogenic temperatures.
  • Figure 2: Abrikosov vortices lattice in BSCCO-2212. (a) Real-space cw-ODMR magnetic field map acquired in tip--sample contact at $T=71K$ after field cooling at $B_z=3.7mT$ and measured under a bias field of 7mT projected along the NV axis. The pixel spacing is 66nm and the total acquisition time is 2 h 40 min. (b) Two-dimensional fast Fourier transform (FFT) modulus of the magnetic field map in (a). The six first-order Bragg peaks reflect the hexagonal symmetry of the triangular Abrikosov vortex lattice. (c) Three-dimensional surface rendering of the magnetic field map shown in (a), highlighting the spatial modulation associated with individual vortices.
  • Figure 3: Abrikosov vortices in a YBCO thin film. (a) Real-space cw-ODMR magnetic field map acquired in tip--sample contact at $T = 3K$ after field cooling at $B_z = 1.18mT$ and measured under an NV-aligned bias field of 1.84mT. The pixel spacing is 66nm and the total acquisition time is 4 h. (b) Three-dimensional surface rendering of the magnetic field map shown in (a), illustrating the spatial variation associated with individual vortices.