Multifunctional magnetooptical sensors for the measurements of magnetic fields, electrical quantities, and temperature

磁传感器应用面临的挑战千差万别。除了磁场量的常规测量之外，磁传感器的一个重要应用领域是电量的间接测量，特别是电流。该项目的目的是研究多功能磁光传感器元件，允许同时光学测量额外的功能参数，特别是温度和电压的测量。这将使用磁光活性亚铁磁石榴石层来实现。读出方案基于饱和磁化强度的温度依赖性，并因此基于磁光法拉第效应的相应变化与层中和磁畴壁的磁化强度响应的特性变化的相关性。对于电压测量，研究了磁电效应的使用。所有的研究都得到了工作中磁畴观测的支持。调查的一个重要部分是致力于各种传感器机制的基础研究和解开的不同信号的影响，同时测量各自的数量。该项目的核心问题是，是否可以用单个多功能传感器检测温度、磁场强度、电流和电压等量的光学、局部和同时测量。这种宽带和光学读出传感器可以决定性地改变测量方法，以确保电气系统的操作安全。

Challenges for the applications of magnetic sensors vary greatly. In addition to the regular measurements of magnetic field quantities an important field of application of magnetic sensors is the indirect measurement of electrical quantities, in particular the electrical current. The aim of the project is to investigate multifunctional magnetooptical sensor elements that allow simultaneous optical measurements of additional functional parameters, in particular the measurement of temperatures and electric voltage. This will be achieved using magnetooptically active ferrimagnetic garnet layers. The read-out scheme is based on the temperature dependence of saturation magnetization and thus the corresponding variation of the magnetooptical Faraday effect in connection with characteristic changes in the magnetization response in the layers and of the magnetic domain walls. For the electric voltage measurements, the use of magnetoelectric effects are investigated. All studies are supported by in-operando magnetic domain observations. An essential part of the investigations is devoted to basic research on the various sensor mechanisms and the unraveling of the different signal influences for the simultaneous measurement of the respective quantities. The question of whether optical, local, and simultaneous measurements of quantities like temperature, magnetic field strength, electric current and electrical voltage can be detected with a single multifunctional sensor is at the center of the project. Such a broadband and optical readout sensor could decisively alter measurement methods to ensure the operational safety in electrical systems.