Frequency Dependency of the Delta-E Effect and the Sensitivity of Delta-E Effect Magnetic Field Sensors

In recent years the delta-E effect has been used for detecting low frequency and low amplitude magnetic fields. Delta-E effect sensors utilize a forced mechanical resonator that is detuned by the delta-E effect upon application of a magnetic field. Typical frequencies of operation are from several kHz to the upper MHz regime. Different models have been used to describe the delta-E effect in those devices, but the frequency dependency has mainly been neglected. With this work we present a simple description of the delta-E effect as a function of the differential magnetic susceptibility χ of the magnetic material. We derive an analytical expression for χ that permits describing the frequency dependency of the delta-E effect of the Young's modulus and the magnetic sensitivity. Calculations are compared with measurements on soft-magnetic (Fe90Co10)78Si12B10 thin films. We show that the frequency of operation can have a strong influence on the delta-E effect and the magnetic sensitivity of delta-E effect sensors. Overall, the delta-E effect reduces with increasing frequency and results in a stiffening of the Young's modulus above the ferromagnetic resonance frequency. The details depend on the Gilbert damping. Whereas for large Gilbert damping the sensitivity continuously decreases with frequency, typical damping values result in an amplification close to the ferromagnetic resonance frequency

Magnetoelastic Coupling and Delta-E Effect in Magnetoelectric Torsion Mode Resonators

Magnetoelectric 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 Cij is derived. Simulations confirm quantitatively that the delta-E effect of the C66 component has the promising potential of significantly increasing the magnetic sensitivity and the maximum normalized frequency change Δfr. However, the electrical excitation of TMs remains challenging and is found to significantly diminish the gain in sensitivity. Experiments reveal the dependency of the sensitivity and Δfr of TMs on the mode number, which differs fundamentally from BMs and is well explained by our model. Because the contribution of C11 to the TMs increases with the mode number, the first-order TM yields the highest magnetic sensitivity. Overall, general insights are gained for the design of high-sensitivity delta-E effect sensors, as well as for frequency tunable devices based on the delta-E effect

Mechanical, Electrical and Magnetic Properties of Ferrogels with Embedded Iron Oxide Nanoparticles Obtained by Laser Target Evaporation: Focus on Multifunctional Biosensor Applications

Hydrogels are biomimetic materials widely used in the area of biomedical engineering and biosensing. Ferrogels (FG) are magnetic composites capable of functioning as magnetic field sensitive transformers and field assisted drug deliverers. FG can be prepared by incorporating magnetic nanoparticles (MNPs) into chemically crosslinked hydrogels. The properties of biomimetic ferrogels for multifunctional biosensor applications can be set up by synthesis. The properties of these biomimetic ferrogels can be thoroughly controlled in a physical experiment environment which is much less demanding than biotests. Two series of ferrogels (soft and dense) based on polyacrylamide (PAAm) with different chemical network densities were synthesized by free-radical polymerization in aqueous solution with N, N'-methylene-diacrylamide as a cross-linker and maghemite Fe2O3 MNPs fabricated by laser target evaporation as a filler. Their mechanical, electrical and magnetic properties were comparatively analyzed. We developed a giant magnetoimpedance (MI) sensor prototype with multilayered FeNi-based sensitive elements deposited onto glass or polymer substrates adapted for FG studies. The MI measurements in the initial state and in the presence of FG with different concentrations of MNPs at a frequency range of 1-300 MHz allowed a precise characterization of the stray fields of the MNPs present in the FG. We proposed an electrodynamic model to describe the MI in multilayered film with a FG layer based on the solution of linearized Maxwell equations for the electromagnetic fields coupled with the Landau-Lifshitz equation for the magnetization dynamics.This work was supported in part within the framework of the state task of the Ministry of Education and Science of Russia 3.6121.2017/8.9; RFBR grants 16-08-00609-a, 18-08-00178, and by the ACTIMAT ELKARTEK grant of the Basque Country Government. Selected studies were made at SGIKER Common Services of UPV-EHU and URFU Common Services. We thank I.V. Beketov, A.A. Chlenova, S.O. Volchkov, V.N. Lepalovskij, A.M. Murzakaev and A.A. Svalova for special support

Визначення мікроелементного складу насіння маку з використанням методу твердофазної спектрофотометрії

Poppy seeds are one of the most important and oldest oil-bearing crops in the world. Therefore, quality control of poppy seeds and food products whose composition contains them as a food additive, is very important. To this end, we have applied procedures for solid-phase spectrophotometric and photometric determining of micro elements in food products.It was established that in determining cadmium and zinc, the best ion exchanger for the group concentration of interfering metal ions is the ion exchanger with the immobilized KO. made it possible to concentrate and determine in the solid phase the ions of Hg(II). Using  enabled selective determining of Pb(II).Selective determining of the Fe(III) ions at pH 3 was conducted using ammonium thiocyanate. Cu(II) was determined photometrically upon masking the ions of Fe(III) employing SPADNS. Based on the data acquired, we have developed a microelement analysis scheme for poppy seeds.It was established that the sample contained, mg/kg: Cu(ІІ) – 5.0; Pb(ІІ) – 0.3, Zn(ІІ) – 50, P(V) – 1,600, K − 550, Na – 20, Ca – 1,500, Mg(II) – 450; Fe(ІІІ) −10; Cd(ІІ) and Hg(ІІ) are absent.The proposed scheme for analysis of poppy seeds is universal and could be applied for microelement analysis of other food products.The procedures employed are characterized by sensitivity and selectivity.Ion exchangers with the immobilized dyes, as well as procedures for the solid-phase spectrophotometric determining, are environmentally safe. They do not require the use of toxic organic reagents.The procedures applied are easy to use.Relative standard deviation in the results does not exceed 0.10. This indicates good reproducibility of the results.Предложена схема твердофазного спектрофотометрического и фотометрического определения микроэлементного состава семян мака, которые используются в качестве пищевой добавки для создания хлебобулочных и кондитерских изделий. Установлено, что в образце содержится, мг/кг: Cu(ІІ) − 5,0; Pb(ІІ) – 0,3, Zn(ІІ) – 50, P(V) – 1600, K − 550, Na – 20, Ca – 1500, Mg(II) – 450; Fe(ІІІ) −10; Cd(ІІ) и Hg(ІІ) – отсутствуют. Использованные методики анализа характеризуются простотой эксперимента, экологической безопасностью, не требуют специального дорогостоящего оборудования, высококвалифицированного персонала и стационарной лабораторииЗапропоновано схему твердофазного спектрофотометричного та фотометричного визначення мікроелементного складу насіння маку, що використовується як харчова добавка для створення хлібобулочних і кондитерських виробів. Встановлено, що у зразку міститься, мг/кг: Cu(ІІ) − 5,0; Pb(ІІ) – 0,3, Zn(ІІ) – 50, P(V) – 1600, K − 550, Na – 20, Ca – 1500, Mg(II) – 450; Fe(ІІІ) −10; Cd(ІІ) та Hg(ІІ) – відсутні. Використані методики аналізу характеризуються простотою експерименту, екологічною безпечністю, не потребують спеціального коштовного обладнання, висококваліфікованого персоналу та стаціонарної лабораторі

Determining the Microelement Composition of Poppy Seeds Using Solid­phase Spectrophotometry Method

Poppy seeds are one of the most important and oldest oil-bearing crops in the world. Therefore, quality control of poppy seeds and food products whose composition contains them as a food additive, is very important. To this end, we have applied procedures for solid-phase spectrophotometric and photometric determining of micro elements in food products.It was established that in determining cadmium and zinc, the best ion exchanger for the group concentration of interfering metal ions is the ion exchanger with the immobilized KO. made it possible to concentrate and determine in the solid phase the ions of Hg(II). Using enabled selective determining of Pb(II).Selective determining of the Fe(III) ions at pH 3 was conducted using ammonium thiocyanate. Cu(II) was determined photometrically upon masking the ions of Fe(III) employing SPADNS. Based on the data acquired, we have developed a microelement analysis scheme for poppy seeds.It was established that the sample contained, mg/kg: Cu(ІІ) – 5.0; Pb(ІІ) – 0.3, Zn(ІІ) – 50, P(V) – 1,600, K − 550, Na – 20, Ca – 1,500, Mg(II) – 450; Fe(ІІІ) −10; Cd(ІІ) and Hg(ІІ) are absent.The proposed scheme for analysis of poppy seeds is universal and could be applied for microelement analysis of other food products.The procedures employed are characterized by sensitivity and selectivity.Ion exchangers with the immobilized dyes, as well as procedures for the solid-phase spectrophotometric determining, are environmentally safe. They do not require the use of toxic organic reagents.The procedures applied are easy to use.Relative standard deviation in the results does not exceed 0.10. This indicates good reproducibility of the results

The Effect of the Open Vase-like Microcapsules Formation with NiFe Double-Hydroxide Walls during Hydrolysis of the Mixture NiSO₄ and FeSO₄ Salt Solution Microdroplets Deposited on the Alkaline Solution Surface

In this work, the conditions for the synthesis of open vase-like microcapsules with a size of 1–5 μm and 20–40 nm walls of NiFe0.3(OH)x layered double hydroxide were studied. These microcapsules were obtained by the rapid hydrolysis of microdroplets of a solution of a mixture of NiSO4 and FeSO4 salts at the surface of an alkali solution. A hypothetical model of successive chemical processes occurring at the interface during synthesis is presented. The features of the “rim” formation around each microcapsule hole from the wall material with a peculiar nozzle-like shape are noted. These microcapsules can be transferred to the surface of a nickel foil using the Langmuir–Schaefer (LS) method. During the transfer process, they are fixed to the surface in an oriented position with a “rim” that contacts the nickel surface. It was established that electrodes made of such a foil with a layer of microcapsules exhibit active electrocatalytic properties in the oxygen evolution reaction during the electrolysis of water in an alkaline medium

Magnetic properties and giant magnetoimpedance of surface modified Co-based amorphous ribbons with carbon covering

Fe3Co66Cr3Si16B12 and Fe6Co60Ni10Si14B10 amorphous ribbons were surface modified in toluene at room temperature. Such a treatment resulted in deposition of thin carbon-based layer. As a result of the carbon covering deposition the stress distribution in the near-surface layers was changed due to partial compensation of the initial quenching stresses. Comparative analysis of magnetic and magnetoimpedance properties of as-quenched and surface modified ribbons confirms changes in effective magnetic anisotropy as a result of surface treatment. An increase of the corrosion resistance of the ribbons with carbon covering can be useful for the development amorphous ribbon based magnetic biosensor

Magnetoimpedance Effect in the Ribbon-Based Patterned Soft Ferromagnetic Meander-Shaped Elements for Sensor Application

Amorphous and nanocrystalline soft magnetic materials have attracted much attention in the area of sensor applications. In this work, the magnetoimpedance (MI) effect of patterned soft ferromagnetic meander-shaped sensor elements has been investigated. They were fabricated starting from the cobalt-based amorphous ribbon using the lithography technique and chemical etching. Three-turn (S1: spacing s = 50 μm, width w = 300 μm, length l = 5 mm; S2: spacing s = 50 μm, width w = 400 μm, length l = 5 mm) and six-turn (S3: s = 40 μm, w = 250 μm, length l = 5 mm; S4: s = 40 μm, w = 250 μm and l = 8 mm) meanders were designed. The ‘n’ shaped meander part was denominated as “one turn”. The S4 meander possesses a maximum MI ratio calculated for the total impedance ΔZ/Z ≈ 250% with a sensitivity of about 36%/Oe (for the frequency of about 45 MHz), and an MI ratio calculated for the real part of the total impedance ΔR/R ≈ 250% with the sensitivity of about 32%/Oe (for the frequency of 50 MHz). Chemical etching and the length of the samples had a strong impact on the surface magnetic properties and the magnetoimpedance. A comparative analysis of the surface magnetic properties obtained by the magneto-optical Kerr technique and MI data shows that the designed ferromagnetic meander-shaped sensor elements can be recommended for high frequency sensor applications focused on the large drop analysis. Here we understand a single large drop as the water-based sample to analyze, placed onto the surface of the MI sensor element either by microsyringe (volue range 0.5−500 μL) or automatic dispenser (volume range 0.1−50 mL)

A protocol for recruiting and analyzing the disease-oriented Russian disc degeneration study (RuDDS) biobank for functional omics studies of lumbar disc degeneration.

Lumbar intervertebral disc degeneration (DD) disease is one of the main risk factors for low back pain and a leading cause of population absenteeism and disability worldwide. Despite a variety of biological studies, lumbar DD is not yet fully understood, partially because there are only few studies that use systematic and integrative approaches. This urges the need for studies that integrate different omics (including genomics and transcriptomics) measured on samples within a single cohort. This protocol describes a disease-oriented Russian disc degeneration study (RuDDS) biobank recruitment and analyses aimed to facilitate further omics studies of lumbar DD integrating genomic, transcriptomic and glycomic data. A total of 1,100 participants aged over 18 with available lumbar MRI scans, medical histories and biological material (whole blood, plasma and intervertebral disc tissue samples from surgically treated patients) will be enrolled during the three-year period from two Russian clinical centers. Whole blood, plasma and disc tissue specimens will be used for genotyping with genome-wide SNP-arrays, glycome profiling and RNA sequencing, respectively. Omics data will be further used for a genome-wide association study of lumbar DD with in silico functional annotation, analysis of plasma glycome and lumbar DD disease interactions and transcriptomic data analysis including an investigation of differential expression patterns associated with lumbar DD disease. Statistical tests applied in each of the analyses will meet the standard criteria specific to the attributed study field. In a long term, the results of the study will expand fundamental knowledge about lumbar DD development and contribute to the elaboration of novel personalized approaches for disease prediction and therapy. Additionally to the lumbar disc degeneration study, a RuDDS cohort could be used for other genetic studies, as it will have unique omics data. Trial registration number NCT04600544