Detecting magnetic field is of great importance for many applications, such as magnetoencephalography and underground prospecting. There have been many magnetometers being widely used since the age of Hall magnetometer. One of the magnetometers, the superconducting quantum interference device, is capable of measuring femtotesla magnetic fields at cryogenic temperature. However, a solid-state magnetometer with femtotesla sensitivity under ambient conditions remains elusive. Here we present a hybrid magnetometer based on the ensemble nitrogen-vacancy centers in diamond with the sensitivity of $(195\pm 60)\mathrm{fT}/{\mathrm{Hz}}^{1/2}$ under ambient conditions, which can be further advanced to $11\mathrm{fT}/{\mathrm{Hz}}^{1/2}$ at 100 Hz with cutting-edge fabrication technologies. Our method will find potential applications in biomagnetism and geomagnetism.

检测磁场对于脑磁图和地下勘探等许多应用具有重要意义。自霍尔磁力计时代以来，已经有许多磁力计被广泛使用。其中一种磁力计，即超导量子干涉装置，能够在低温下测量飞特斯拉磁场。然而，在环境条件下具有飞特斯拉灵敏度的固态磁力计仍然难以捉摸。在这里，我们提出了一种基于钻石中整体氮空位中心的混合磁力计，其灵敏度为$(195\pm 60)\mathrm{fT}/{\mathrm{赫兹}}^{\mathrm{1个}/\mathrm{2个}}$在环境条件下，可以进一步推进到$11\mathrm{fT}/{\mathrm{赫兹}}^{\mathrm{1个}/\mathrm{2个}}$以 100 Hz 的尖端制造技术。我们的方法将在生物磁学和地磁学中找到潜在的应用。