Magnetoelastic sensors for the detection of low-frequency and low-amplitude magnetic fields are in the focus of research for more than 30 years. In order to minimize the limit of detection (LOD) of such sensor systems, it is of high importance to understand and to be able to quantify the relevant noise sources. In this contribution, cantilever-type electromechanical and magnetoelastic resonators, respectively, are comprehensively investigated and mathematically described not only with regard to their phase sensitivity but especially to the extent of the sensor-intrinsic phase noise. Both measurements and calculations reveal that the fundamental LOD is limited by additive phase noise due to thermal-mechanical noise of the resonator, i.e. by thermally induced random vibrations of the cantilever, and by thermal-electrical noise of the piezoelectric material. However, due to losses in the magnetic material parametric flicker phase noise arises, limiting the overall performance. In particular, it is shown that the LOD is virtually independent of the magnetic sensitivity but is solely determined by the magnetic losses. Instead of the sensitivity, the magnetic losses, represented by the material’s effective complex permeability, should be considered as the most important parameter for the further improvement of such sensors in the future. This implication is not only valid for magnetoelastic cantilevers but also applies to any type of magnetoelastic resonator. [2020-0219]

中文翻译：

---

压电驱动磁弹性悬臂梁的基本噪声限值和灵敏度

用于检测低频和低振幅磁场的磁弹性传感器是 30 多年来的研究重点。为了最大限度地减少此类传感器系统的检测限 (LOD)，了解并能够量化相关噪声源非常重要。在这一贡献中，分别对悬臂式机电谐振器和磁弹性谐振器进行了全面的研究和数学描述，不仅涉及它们的相位灵敏度，而且特别涉及传感器固有相位噪声的范围。测量和计算都表明，基本 LOD 受到由谐振器的热机械噪声引起的附加相位噪声的限制，即悬臂的热致随机振动，以及压电材料的热电噪声。然而，由于磁性材料参数闪烁中的损耗会产生相位噪声，从而限制了整体性能。特别是，它表明 LOD 实际上与磁灵敏度无关，而仅由磁损耗决定。代替灵敏度，以材料的有效复磁导率表示的磁损耗应被视为未来进一步改进此类传感器的最重要参数。这种含义不仅适用于磁弹性悬臂梁，而且适用于任何类型的磁弹性谐振器。[2020-0219] 结果表明，LOD 实际上与磁灵敏度无关，而仅由磁损耗决定。代替灵敏度，以材料的有效复磁导率表示的磁损耗应被视为未来进一步改进此类传感器的最重要参数。这种含义不仅适用于磁弹性悬臂梁，而且适用于任何类型的磁弹性谐振器。[2020-0219] 结果表明，LOD 实际上与磁灵敏度无关，而仅由磁损耗决定。代替灵敏度，以材料的有效复磁导率表示的磁损耗应被视为未来进一步改进此类传感器的最重要参数。这种含义不仅适用于磁弹性悬臂梁，而且适用于任何类型的磁弹性谐振器。[2020-0219] 这种含义不仅适用于磁弹性悬臂梁，而且适用于任何类型的磁弹性谐振器。[2020-0219] 这种含义不仅适用于磁弹性悬臂梁，而且适用于任何类型的磁弹性谐振器。[2020-0219]