Nitrogen vacancy (NV) centers, optically active atomic defects in diamond, have been widely applied to emerging quantum sensing, imaging, and network efforts, showing unprecedented field sensitivity and nanoscale spatial resolution. Many of these advantages derive from their excellent quantum-coherence, controllable entanglement, and high fidelity of operations, enabling opportunities to outperform the classical counterpart. Exploiting this cutting-edge quantum metrology, we report noninvasive measurement of intrinsic spin fluctuations of magnetic insulator thin films with a spontaneous out-of-plane magnetization. The measured field dependence of NV relaxation rates is well correlated to the variation of magnon density and band structure of the magnetic samples, which are challenging to access by the conventional magnetometry methods. Our results highlight the significant opportunities offered by NV centers in diagnosing the noise environment of functional magnetic elements, providing valuable information to design next-generation, high-density, and scalable spintronic devices.
@article{arxiv.2009.02883,
title = {Quantum Sensing of Spin Fluctuations of Magnetic Insulator Films with Perpendicular Anisotropy},
author = {Eric Lee-Wong and Jinjun Ding and Xiaoche Wang and Chuanpu Liu and Nathan J. McLaughlin and Hailong Wang and Mingzhong Wu and Chunhui Rita Du},
journal= {arXiv preprint arXiv:2009.02883},
year = {2021}
}