Strain-resistance effect of metallic sensor layers in the antiferromagnetic state

这项提议的目的是研究一种鲜为人知的、与反铁磁相相关的相当高的应变阻力效应。为此，我们制备了金属薄膜，并对其进行了详细的研究。金属薄膜可用作压力和力等力学量的传感层。我们的初步工作证明了铬金属层的压阻效应及其与反铁磁态(AFM)的耦合。因此，拟议的项目以含铬层为基础，现在用低浓度的元素如锰、Ru和其他元素进行改性，以便将反铁磁-顺磁转变温度Tnéel提高到更高的值。其主要特性是高应变灵敏度、低温度系数(TKR)、高电阻稳定性和可能的最高应用温度。其目的是获得尽可能高的应变灵敏度，恒定或略高于温度，具有低TKR和高稳定性。然后合成了具有已知的高奈尔温度的含锰化合物，这些化合物已经在反铁磁性自旋电子学的研究中发挥了作用，但其压阻性能尚未被研究。这些材料包括具有810K到1500K超高Néel温度的二元化合物，如MnNi、MnPd、MnPt、MnIr和Mn2Au，其中一些化合物是通过溅射沉积成薄膜的，并对其结构和性能进行了研究。此外，还用EDX、XPS、X射线衍射仪和磁化率测试等手段对涂层进行了表征。合适的层作为功能层沉积在压力传感器主体上，构造为测量电桥，然后充分表征和优化其作为传感器层的适宜性。在高温下具有高应变灵敏度的金属反铁磁薄膜的研究和优化在传感器技术中具有有趣的应用潜力。此外，这些结果可能会导致对反铁磁层的自旋电子学也有用的发现。

The aim of this proposal is to investigate a hardly known, quite high strain-resistance effect linked to the antiferromagnetic phase. For this purpose, metallic thin films, which can be used as sensor layers for mechanical quantities, such as pressure and force are deposited and investigated in detail. The piezoresistive effect and its coupling to the antiferromagnetic state (AFM) of metal layers made of chromium has been proven by our preliminary work. The proposed project is therefore based on chromium-containing layers which are now modified with low concentrations of elements such as Mn, Ru and others in order to shift the antiferro-paramagnetic transition temperature TNéel to higher values. The main properties are a high strain sensitivity, a low temperature coefficient (TKR), a high resistance stability and the highest possible application temperatures. The aim is to achieve the highest possible strain sensitivity, constant or slightly increasing over temperature, with low TKR and high stability. Then manganese-containing compounds with known high Néel temperatures are produced, which already play a role in the research of antiferromagnetic spintronics, but whose piezoresistive properties have not yet been investigated. These materials include binary compounds such as MnNi, MnPd, MnPt, MnIr and Mn2Au with extraordinarily high Néel temperatures of 810 K to 1500 K. Some of these compounds are deposited as thin films by sputtering, structured and investigated for their properties. In addition, the coatings are characterized by EDX, XPS, XRD and magnetic susceptibility measurements. Suitable layers are deposited as functional layers on pressure sensor bodies, structured as measuring bridges and then fully characterized and optimized with respect to their suitability as sensor layers. The research and optimization of metallic antiferromagnetic thin films with high strain sensitivities at high application temperatures promises an interesting application potential in sensor technology. In addition, the results can lead to findings that are also useful for the spintronics of antiferromagnetic layers.