The pursuit for advanced magnetoelectric field sensors has gained momentum, driven by applications in various fields, ranging from biomedical applications to soft robotics and the automotive sector. In this context, a capacitive read-out based magnetostrictive polymer composite (MPC) sensor element is introduced, offering a new perspective on magnetic field detection. The sensor element's unique feature is the possibility to independently tailor its mechanical and magnetic properties.
View Article and Find Full Text PDFIn recent years, extensive research on noble metal-TiO nanocomposites has demonstrated their crucial role in various applications such as water splitting, self-cleaning, CO reduction, and wastewater treatment. The structure of the noble metal-TiO nanocomposites is critical in determining their photocatalytic properties. Numerous studies in the literature describe the preparation of these nanocomposites with various shapes and sizes to achieve tunable photocatalytic performance.
View Article and Find Full Text PDFFabricating thin metal layers and particularly observing their formation process in situ is of fundamental interest to tailor the quality of such a layer on polymers for organic electronics. In particular, the process of high power impulse magnetron sputtering (HiPIMS) for establishing thin metal layers has sparsely been explored in situ. Hence, in this study, we investigate the growth of thin gold (Au) layers with HiPIMS and compare their growth with thin Au layers prepared by conventional direct current magnetron sputtering (dcMS).
View Article and Find Full Text PDFIntroducing metallic nanoparticles, such as Au, on a substrate as a surfactant or wetting inducer has been demonstrated as a simple but effective way to facilitate the formation of ultra-thin silver layers (UTSLs) during the subsequent Ag deposition. However, most studies have paid much attention to the applications of UTSLs assisted by metallic surfactants but neglected the underlying mechanisms of how the metallic surfactant affects the formation of UTSL. Herein, we have applied grazing-incidence wide-/small-angle X-ray scattering to reveal the effects of the Au surfactant or seed layer (pre-deposited Au nanoparticles) on the formation of UTSL by high-power impulse magnetron sputter deposition (HiPIMS) on a zinc oxide (ZnO) thin film.
View Article and Find Full Text PDFPlasmons have facilitated diverse analytical applications due to the boosting signal detectability by hot spots. In practical applications, it is crucial to fabricate straightforward, large-scale, and reproducible plasmonic substrates. Dewetting treatment, applying direct thermal annealing of metal films, has been used as a straightforward method in the fabrication of such plasmonic nanostructures.
View Article and Find Full Text PDFMagnetoelastic micro-electromechanical systems (MEMS) are integral elements of sensors, actuators, and other devices utilizing magnetostriction for their functionality. Their sensitivity typically scales with the saturation magnetostriction and inversely with magnetic anisotropy. However, large saturation magnetostriction and small magnetic anisotropy make the magnetoelastic layer highly susceptible to minuscule anisotropic stress.
View Article and Find Full Text PDFIn recent years, defective TiO has caught considerable research attention because of its potential to overcome the limits of low visible light absorption and fast charge recombination present in pristine TiO photocatalysts. Among the different synthesis conditions for defective TiO, ambient pressure hydrogenation with the addition of Ar as inert gas for safety purposes has been established as an easy method to realize the process. Whether the Ar gas might still influence the resulting photocatalytic properties and defective surface layer remains an open question.
View Article and Find Full Text PDFA comprehensive understanding of the linear/nonlinear dynamic behavior of wireless microresonators is essential for micro-electromechanical systems (MEMS) design optimization. This study investigates the dynamic behaviour of a magnetoelectric (ME) microresonator, using a finite element method (FEM) and machine learning algorithm. First, the linear/nonlinear behaviour of a fabricated thin-film ME microactuator is assessed in both the time domain and frequency spectrum.
View Article and Find Full Text PDFPattern fabrication by self-assembly of diblock copolymers is of significant interest due to the simplicity in fabricating complex structures. In particular, polystyrene--poly-4-vinylpyridine (PS--P4VP) is a fascinating base material as it forms an ordered micellar structure on silicon surfaces. In this work, silver (Ag) is applied using direct current magnetron sputter deposition and high-power impulse magnetron sputter deposition on an ordered micellar PS--P4VP layer.
View Article and Find Full Text PDFCertain molecules act as biomarkers in exhaled breath or outgassing vapors of biological systems. Specifically, ammonia (NH) can serve as a tracer for food spoilage as well as a breath marker for several diseases. H gas in the exhaled breath can be associated with gastric disorders.
View Article and Find Full Text PDFA novel combined setup of a Haberland type gas aggregation source and a secondary radio frequency discharge is used to generate, confine, and coat nanoparticles over much longer time scales than traditional in-flight treatment. The process is precisely monitored using localized surface plasmon resonance and Fourier-transform infrared spectroscopy as diagnostics. They indicate that both untreated and treated particles can be confined for extended time periods (at least one hour) with minimal losses.
View Article and Find Full Text PDFMetal oxide gas sensors are of great interest for applications ranging from lambda sensors to early hazard detection in explosive media and leakage detection due to their superior properties with regard to sensitivity and lifetime, as well as their low cost and portability. However, the influence of ambient gases on the gas response, energy consumption and selectivity still needs to be improved and they are thus the subject of intensive research. In this work, a simple approach is presented to modify and increase the selectivity of gas sensing structures with an ultrathin polymer thin film.
View Article and Find Full Text PDFNanomaterials (Basel)
January 2023
Colored imaging of magnetic nanoparticles (MNP) is a promising noninvasive method for medical applications such as therapy and diagnosis. This study investigates the capability of the magnetoelectric sensor and projected gradient descent (PGD) algorithm for colored particle detection. In the first step, the required circumstances for image reconstruction are studied via a simulation approach for different signal-to-noise ratios (SNR).
View Article and Find Full Text PDFHere, a 4N-in-1 hybrid substrate concept (nanocolumnar structures, nanocrack network, nanoscale mixed oxide phases, and nanometallic structures) for ultra-sensitive and reliable photo-induced-enhanced Raman spectroscopy (PIERS), is proposed. The use of the 4N-in-1 hybrid substrate leads to an ≈50-fold enhancement over the normal surface-enhanced Raman spectroscopy, which is recorded as the highest PIERS enhancement to date. In addition to an improved Raman signal, the 4N-in-1 hybrid substrate provides a high detection sensitivity which may be attributed to the activation possibility at extremely low UV irradiation dosage and prolonged relaxation time (long measurement time).
View Article and Find Full Text PDFRandom networks of nanoparticle-based memristive switches enable pathways for emulating highly complex and self-organized synaptic connectivity together with their emergent functional behavior known from biological neuronal networks. They therefore embody a distinct class of neuromorphic hardware architectures and provide an alternative to highly regular arrays of memristors. Especially, networks of memristive nanoparticles (NPs) poised at the percolation threshold are promising due to their capabilities of showing brain-like activity such as critical dynamics or long-range temporal correlation (LRTC), which are closely connected to the computational capabilities in biological neuronal networks.
View Article and Find Full Text PDFMiniaturized piezoelectric/magnetostrictive contour-mode resonators have been shown to be effective magnetometers by exploiting the ΔE effect. With dimensions of ~100-200 μm across and <1 μm thick, they offer high spatial resolution, portability, low power consumption, and low cost. However, a thorough understanding of the magnetic material behavior in these devices has been lacking, hindering performance optimization.
View Article and Find Full Text PDFWith this work we introduce a novel memristor in a lateral geometry whose resistive switching behaviour unifies the capabilities of bipolar switching with decelerated diffusive switching showing a biologically plausible short-term memory. A new fabrication route is presented for achieving lateral nano-scaled distances by depositing a sparse network of carbon nanotubes (CNTs) via spin-coating of a custom-made CNT dispersion. Electrochemical metallization-type (ECM) resistive switching is obtained by implanting AgAu nanoparticles with a Haberland-type gas aggregation cluster source into the nanogaps between the CNTs and shows a hybrid behaviour of both diffusive and bipolar switching.
View Article and Find Full Text PDFSensors (Basel)
January 2022
Imaging of magnetic nanoparticles (MNPs) is of great interest in the medical sciences. By using resonant magnetoelectric sensors, higher harmonic excitations of MNPs can be measured and mapped in space. The proper reconstruction of particle distribution via solving the inverse problem is paramount for any imaging technique.
View Article and Find Full Text PDFRecently, Delta-E effect magnetic field sensors based on exchange-biased magnetic multilayers have shown the potential of detecting low-frequency and small-amplitude magnetic fields. Their design is compatible with microelectromechanical system technology, potentially small, and therefore, suitable for arrays with a large number N of sensor elements. In this study, we explore the prospects and limitations for improving the detection limit by averaging the output of N sensor elements operated in parallel with a single oscillator and a single amplifier to avoid additional electronics and keep the setup compact.
View Article and Find Full Text PDFLarge-scale fabrication of metal cluster layers for usage in sensor applications and photovoltaics is a huge challenge. Physical vapor deposition offers large-scale fabrication of metal cluster layers on templates and polymer surfaces. In the case of aluminum (Al), only little is known about the formation and interaction of Al clusters during sputter deposition.
View Article and Find Full Text PDFTiO/CuO/CuO multi-nanolayers highly sensitive toward volatile organic compounds (VOCs) and H have been grown in various thicknesses by a cost-effective and reproducible combined spray-sputtering-annealing approach. The ultrathin TiO films were deposited by spray pyrolysis on top of sputtered-annealed CuO/CuO nanolayers to enhance their gas sensing performance and improve their protection against corrosion at high operating temperatures. The prepared heterostructures were investigated using scanning electron microscopy (SEM), X-ray diffraction (XRD), and ultraviolet visible (UV-vis) and micro-Raman spectroscopy.
View Article and Find Full Text PDFThe treatment of refractory epilepsy via closed-loop implantable devices that act on seizures either by drug release or electrostimulation is a highly attractive option. For such implantable medical devices, efficient and low energy consumption, small size, and efficient processing architectures are essential. To meet these requirements, epileptic seizure detection by analysis and classification of brain signals with a convolutional neural network (CNN) is an attractive approach.
View Article and Find Full Text PDFCopper (Cu) as an excellent electrical conductor and the amphiphilic diblock copolymer polystyrene-block-poly(ethylene oxide) (PS-b-PEO) as a polymer electrolyte and ionic conductor can be combined with an active material in composite electrodes for polymer lithium-ion batteries (LIBs). As interfaces are a key issue in LIBs, sputter deposition of Cu contacts on PS-b-PEO thin films with high PEO fraction is investigated with in situ grazing-incidence small-angle X-ray scattering (GISAXS) to follow the formation of the Cu layer in real-time. We observe a hierarchical morphology of Cu clusters building larger Cu agglomerates.
View Article and Find Full Text PDFMagnetoelectric resonators have been studied for the detection of small amplitude and low frequency magnetic fields via the delta-E effect, mainly in fundamental bending or bulk resonance modes. Here, we present an experimental and theoretical investigation of magnetoelectric thin-film cantilevers that can be operated in bending modes (BMs) and torsion modes (TMs) as a magnetic field sensor. A magnetoelastic macrospin model is combined with an electromechanical finite element model and a general description of the delta-E effect of all stiffness tensor components is derived.
View Article and Find Full Text PDF