Keyser Ailsa K V, Burnett Jonathan J, Kubatkin Sergey E, Danilov Andrey V, Oxborrow Mark, de Graaf Sebastian E, Lindström Tobias
National Physical Laboratory, Hampton Road, Teddington TW11 0LW, UK; Imperial College London, Exhibition Road, SW7 2AZ, UK.
National Physical Laboratory, Hampton Road, Teddington TW11 0LW, UK.
J Magn Reson. 2020 Dec;321:106853. doi: 10.1016/j.jmr.2020.106853. Epub 2020 Oct 20.
We establish a testbed system for the development of high-sensitivity Electron Spin Resonance (ESR) techniques for small samples at cryogenic temperatures. Our system consists of a NbN thin-film planar superconducting microresonator designed to have a concentrated mode volume to couple to a small amount of paramagnetic material, and to be resilient to magnetic fields of up to 400mT. At 65mK we measure high-cooperativity coupling (C≈19) to an organic radical microcrystal containing 10 spins in a pico-litre volume. We detect the spin-lattice decoherence rate via the dispersive frequency shift of the resonator. Techniques such as these could be suitable for applications in quantum information as well as for pulsed ESR interrogation of very few spins to provide insights into the surface chemistry of, for example, the material defects in superconducting quantum processors.
我们建立了一个测试平台系统，用于开发在低温下对小样品的高灵敏度电子自旋共振（ESR）技术。我们的系统由一个氮化铌薄膜平面超导微谐振器组成，该谐振器设计为具有集中的模式体积，以耦合少量顺磁材料，并能抵抗高达400mT的磁场。在65mK时，我们测量到与皮升体积中含有10个自旋的有机自由基微晶的高协同耦合（C≈19）。我们通过谐振器的色散频率偏移来检测自旋-晶格退相干率。这类技术可能适用于量子信息应用，以及对极少数自旋进行脉冲ESR询问，以深入了解例如超导量子处理器中的材料缺陷等表面化学情况。
