Multimodal Quantum Sensing Platform for Ultrathin Spintronic Materials and Devices

磁性传感器技术的进步与磁性材料和器件的进步密切相关。目前，用于表征块状磁性材料的庞大传感器工具包对纳米自旋电子器件和最近出现的原子薄磁体越来越不敏感，它们的信号太弱，无法用传统仪器测量。该项目将展示一种独特的纳米级磁强计，具有内在的量子力学操作，以应对这一及时的挑战。这种所谓的“量子传感器”是基于钻石晶格中一个孤立的缺陷，即钻石中的氮空位中心。目标是开发新的技术和硬件系统，将这些传感器整合到一种仪器中，用于表征超薄磁性材料的静态和动态磁性。使能的测量模式将被用来阐明磁性相变的性质以及新型材料中磁性原子之间的相互作用，从而催化向更高性能的磁性器件迈进。此外，该项目将为K-12教室开发可远程访问的界面和教育资源，以探索对单量子态的操纵。对年轻学生来说，这种亲身接触量子科学的机会有望培养不同群体最终参与到科学和工程领域的职业生涯中。越来越多的传统体磁探测器，如基于超导量子干涉装置的商用磁强计，无法检测到来自原子薄磁体和纳米自旋电子器件的微小信号。近年来，金刚石中的氮空位中心已经成为一种能够在纳米尺度上接近超薄材料样品的最高磁强计，对于从样品磁化中检测快速衰减的偶极场至关重要。该项目旨在建立一个基于氮空位中心的平台技术，用于对静态磁化以外的多模式磁性进行非侵入性探测，以及对各种磁性材料进行非侵入性探测。该平台将演示由活性物质激发和热力学波动产生的动态磁场的检测，以及开发用于超薄样品的交流磁化率和自旋共振的模块。先进的量子控制序列将延长量子传感器的相干时间，实现超过商业仪器的灵敏度。这里开发的独特能力有望解决二维极限中的铁磁性和反铁磁性的公开问题，并指导下一代磁存储器、基于自旋的晶体管和超薄微波组件的开发。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Advancement in magnetic sensor technologies is intimately intertwined with progress in magnetic materials and devices. Currently, the vast sensor toolkit for characterizing bulk magnetic materials is increasingly insensitive to nano-spintronic devices and recently-emerged atomically thin magnets, whose signals are too weak to be measured by conventional instruments. This project will demonstrate a unique nanoscale magnetometer with intrinsic quantum mechanical operation to address this timely challenge. This so-called “quantum sensor” is based on an isolated defect in the diamond lattice, known as the nitrogen-vacancy center in diamond. The goal is to develop novel technique and hardware systems to incorporate these sensors into an instrument for characterizing both the static and dynamic magnetic properties of ultrathin magnetic materials. The enabled measurement modes will be used to elucidate the nature of the magnetic phase transition and the interactions between magnetic atoms in novel materials, catalyzing progress towards higher performance magnetic devices. In addition, the project will develop a remotely accessible interface and educational resources for K-12 classrooms to explore manipulation of single quantum states. This hands-on exposure to quantum science for young students is expected to nurture the eventual participation of diverse groups in careers in science and engineering.Increasingly, conventional probes of bulk magnetism, such as commercial magnetometers based on the superconducting quantum interference device, are unable to detect the minuscule signals from atomically thin magnets and nano-spintronic devices. In recent years, the nitrogen-vacancy center in diamond has emerged as a superlative magnetometer capable of nanoscale proximity to ultrathin material samples, crucial for detecting the rapidly decaying dipolar fields from sample magnetizations. This project aims to establish a platform technology based on nitrogen-vacancy centers for the non-invasive probing of multi-modal magnetic properties, beyond static magnetization, and of diverse magnetic materials, beyond ferromagnets. The platform will demonstrate detection of dynamical magnetic fields created by both active material excitation and thermodynamic fluctuations, as well as develop modules for ac susceptibility and spin resonance in ultrathin samples. Advanced quantum control sequences will extend the coherence time of quantum sensors to achieve sensitivity surpassing commercial instruments. The unique capabilities developed here are expected to address open questions in ferromagnetism and antiferromagnetism in the two-dimensional limit and guide the development of next-generation magnetic memory, spin-based transistors, and ultrathin microwave components.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.