In this work, we study the influence of the magnetic proximity effect (MPE) in Pt on the total magnetic moment of thin film trilayer systems consisting of the ferromagnet (FM) Co adjacent to the heavy metals (HMs) Pt and Ta. We investigate the trilayer systems HM 1 /FM/HM 2 with different stacking order as well as a reference bilayer without any MPE. X-ray resonant magnetic reflectivity (XRMR) is a powerful tool to probe induced magnetism, especially when buried at interfaces in a multilayer. By using XRMR, we are able to obtain magnetic depth profiles of the structural, optical and magnetic parameters. By fitting the experimental data with a Gaussian-like magnetooptic profile taking the structural roughness at the interface into account, we can extract the magnetic moment of the spin-polarized layer. Comparing the obtained moments to the measured total moment of the sample, we can determine the impact of the MPE on the total magnetic moment of the system. Such information can be critical for analyzing spin transport experiments, including spin-orbit torque and spin Hall angle measurements, where the saturation magnetization M s has to be taken into account. Therefore, by combining magnetization measurements and XRMR methods we were able to get a complete picture of the magnetic moment distribution in these trilayer systems containing spin-polarized Pt.

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The advantages of planar Hall effect (PHE) sensors-their thermal stability, very low detection limits, and high sensitivities-have supported a wide range of advanced applications such as nano-Tesla (nT) magnetometers, current sensing, or low magnetic moment detection in lab-on-a-chip devices. In this review we outline the background and implications of these PHE sensors, starting from fundamental physics through their technological evolution over the past few decades. Key parameters affecting the performance of these sensors, including noise from different sources, thermal stability, and magnetoresistance magnitudes are discussed. The progression of sensor geometries and junctions from disk, cross-to-bridge, ring, and ellipse configuration is also reviewed. The logical sequence of these structures from single magnetoresistive layers to bi-, tri-layers, and spin-valves is also covered. Research contributions to the development of these sensors are highlighted with a focus on microfluidics and flexible sensorics. This review serves as a comprehensive resource for scientists who wish to use PHE for fundamental research or to develop new applications and devices. The conclusions from this report will benefit the development, production, and performance evaluation of PHE-based devices and microfluidics, as well as set the stage for future advances.

X-ray resonant magnetic reflectivity (XRMR) is a powerful method to determine the optical, structural and magnetic depth profiles of a variety of thin film systems. Here, we investigate samples of different complexity all measured at the Pt L 3 absorption edge to determine the optimal procedure for the analysis of the experimental XRMR curves, especially for nontrivial bi- and multilayer samples that include differently bonded Pt from layer to layer. The software tool ReMagX is used to fit these data and model the magnetooptic depth profiles based on a highly adaptable layer stack which is modified to be a more precise and physically consistent representation of the real multilayer system. Various fitting algorithms, iterative optimization approaches and a detailed analysis of the asymmetry ratio features as well as χ 2 (goodness of fit) landscapes are utilized to improve the agreement between measurements and simulations. We present a step-by-step analysis procedure tailored to the Pt thin film systems to take advantage of the excellent magnetic sensitivity and depth resolution of XRMR.

Abstract-The paper is devoted to the study of microwave analogue of Tamm states appearing at the boundary of two different periodical chain-like structures in contact. A comparison of numerical and experimental data is provided for periodical chains of quadripoles modelling our system. As it turns out, at the point of contact of two different periodic structures, significant concentration of electromagnetic wave energy takes place. The corresponding concentration of energy is quite similar to those characteristics for Tamm states concentration which takes place at the boundary between two adjacent photonic crystals. We use the term microwave analogue of Tamm states for the considered periodic chain-like structures.

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X-ray resonant magnetic reflectivity (XRMR) allows for the simultaneous measurement of structural, optical, and magneto-optic properties and depth profiles of a variety of thin film samples. However, a same-beamtime same-sample systematic quantitative comparison of the magnetic properties observed using XRMR and x-ray magnetic circular dichroism (XMCD) is still pending. Here, the XRMR results (Pt L 3 absorption edge) for the magnetic proximity effect in Pt deposited on the two different ferromagnetic materials Fe and Co 33 Fe 67 are compared with quantitatively analyzed XMCD results. The obtained results are in very good quantitative agreement between the absorptionbased (XMCD) and reflectivity-based (XRMR) techniques, taking into account an ab initio calculated magneto-optic conversion factor for the XRMR analysis. Thus, it is shown that XRMR provides quantitative reliable spin depth profiles important for spintronic and spin caloritronic transport phenomena at this type of magnetic interfaces.

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