Electron Spin Resonance with up to 20 Spin Sensitivity Measured using a Superconducting Flux Qubit
arXiv:2003.09131 · doi:10.1063/1.5144722
Abstract
We report on electron spin resonance spectroscopy measurements using a superconducting flux qubit with a sensing volume of 6 fl. The qubit is read out using a frequency-tunable Josephson bifurcation amplifier, which leads to an inferred measurement sensitivity of about 20 spins in a 1 s measurement. This sensitivity represents an order of magnitude improvement when compared with flux-qubit schemes using a dc-SQUID switching readout. Furthermore, noise spectroscopy reveals that the sensitivity is limited by flicker () flux noise.
4 pages, 4 figures