Magnetoelastic Villari Effect in Ferrite Materials for Force and Stress Sensors Working in Low Magnetizing Field Region

The following paper presents the original results of investigation on the magnetoelastic properties of ferrite materials magnetized in low field region, which could be utilized in development of force and stress sensors. The objects of investigation were two ferrite materials (manganese-zinc Mn-Zn and nickel-zinc Ni-Zn). The magnetoelastic characteristics of the materials were investigated with the special measurement system, allowing measurement of magnetic parameters of the ferrite materials magnetized with low fields under the influence of the compressive stress. The obtained results indicate that there is a strong correlation between the magnetic properties of the material in low magnetizing field region, and applied mechanical stress, which allows development of the magnetoelastic stress or force sensor with ferrite core working in low magnetizing field region

Growth of Ternary and Quaternary ZnSe Compounds with Transition Metals by Chemical Vapor Transport

Halogen transport method was applied to grow the crystals of solid solutions of ZnSe and transition metals at the temperature far below the melting point and phase transition temperature. The large crystals of ZnMnSe, ZnFeSe, ZnNiSe and ZnFeSSe were obtained. The technological parameters and shape of the quartz reactor were chosen for growth of a large crystal by self-nucleation; the transparent quartz furnace enabled the control of nucleation by visual observation. The parameters of crystal growth were determined. The crystal quality was estimated by X-ray diffraction method. The composition of crystals was determined by electron microprobe analysis and energy dispersive X-ray fluorescence analysis

Magnetoelastic Villari Effect in Structural Steel Magnetized in the Rayleigh Region

The following paper presents the results of investigation on the magnetoelastic Villari effect in structural steel magnetized in the so-called Rayleigh region, which corresponds to relatively low magnetizing fields, much lower than coercive field. Two grades of structural steel were investigated during the performed measurements. Obtained results indicate significant correlation between applied mechanical stress and magnetic properties of the investigated materials

Open source ELMER software based FEM modeling of waveguides and resonant cavities for microwave heating and drying devices

Microwave devices are widely used in the industry and in the specialized laboratory analyses. Development of such devices requires the possibility of modeling of microwave energy distribution in the specific resonant chambers. Until now, such modeling was possible only with the use of commercial software or was limited to specific cases. The paper presents an open-source module for ELMER software for solving timeharmonic Maxwell’s equations, allowing modeling of microwave waveguide lines. Three test cases of different resonant chambers are investigated at 2.45 GHz frequency. Modeling results obtained from the open-source ELMER Vectorial Helmholtz module show that the application of this software can be effective in R&D works, enabling high-tech small and medium enterprises involvement in advanced microwave technology

Open source ELMER software based FEM modeling of waveguides and resonant cavities for microwave heating and drying devices

Microwave devices are widely used in the industry and in the specialized laboratory analyses. Development of such devices requires the possibility of modeling of microwave energy distribution in the specific resonant chambers. Until now, such modeling was possible only with the use of commercial software or was limited to specific cases. The paper presents an open-source module for ELMER software for solving timeharmonic Maxwell’s equations, allowing modeling of microwave waveguide lines. Three test cases of different resonant chambers are investigated at 2.45 GHz frequency. Modeling results obtained from the open-source ELMER Vectorial Helmholtz module show that the application of this software can be effective in R&D works, enabling high-tech small and medium enterprises involvement in advanced microwave technology

Precipitates in Cd1−x\text{}_{1-x}Nix\text{}_{x}Se Crystals Grown by the Bridgman Method

Single crystals of Cd$\text{}_{1-x}$Ni$\text{}_{x}$Se alloys (x ranging from 0 to 0.075) were investigated using electron microprobe and X-ray diffraction. The analysis shows the presence of Ni-Se precipitates. The solubility limit of Ni is estimated to be 0.008

Discrete Inverse Transformation for Eddy Current Tomography

Paper presents results of a discrete inverse tomography transformation on exemplary results from eddy current tomography setup. Eddy current phenomena is highly non-linear and measurement results are ill-posed function of distribution of physical properties of the matter (mostly electrical conductivity and magnetic permeability). Thus the inverse transformation (reconstruction of objects shape) is based on an optimization algorithm in which objects model is described as a discrete array. With the usage of Finite Element Method (FEM) tomography measurement process is reconstructed and modelling results are compared with the measurement

Functional Properties of Monolayer and Bilayer Graphene Hall-Effect Sensors

The paper describes the design, development, and investigation of a new type of Hall-effect sensors of a magnetic field made of graphene. The epitaxial growth of high-quality graphene structures was performed using a standard hot-wall CVD reactor, which allows for easy integration with an existing semiconductors production technologies. The functional properties of developed Hall-effect sensors based on graphene were investigated on special experimental setup utilizing Helmholtz coils as a source of reference magnetic field. Monolayer and quasi-free-standing bilayer graphene structures were tested. Results presented in the paper indicate that graphene is very promising material for development of Hall-effect sensors. Developed graphene Hall-effect sensor exhibit highly linear characteristics and high magnetic field sensitivity

Temperature Resistance of Magnetoelastic Characteristics of 13CrMo4-5 Constructional Steel

In the paper the results of investigation on tensile stresses dependence of magnetoelastic characteristics of cores made of 13CrMo4-5 constructional steel are presented. In the investigation step-cooling test treated samples were used. The step-cooling test process is a type of heat treatment simulating effects of passing time and environmental conditions (temperature and stress) on the sample. In the paper the method of testing the influence of stresses on the magnetic characteristics is presented. Frame shaped samples ensured a closed magnetic circuit and homogeneous distribution of stress. It was found that step-cooling test does not significantly influence the magnetoelastic characteristics and the structure of the samples. On the other hand, then tensile stresses significantly change the magnetic characteristics of 13CrMo4-5 constructional steel. That confirms the possibility of using measurements based on the magnetoelastic effect in the stress assessment for industrial non destructing testing of steel constructions

Electrical, Magnetic, and Structural Properties of Sn1−x\text{}_{1-x}Mnx\text{}_{x}Te Layers Grown by Molecular Beam Epitaxy

Layers of Sn$\text{}_{1-x}$Mn$\text{}_{x}$Te (x ≤ 0.1) with thickness 0.2-2 μm were grown by molecular beam epitaxy on BaF$\text{}_{2}$ substrates with a 0.01-1 μm thick SnTe buffer layer. Both SnTe and Sn$\text{}_{1-x}$Mn$\text{}_{x}$Te layers show metallic p-type conductivity with conducting hole concentrations (at T=77 K) p$\text{}_{77}$=7×10$\text{}^{19}$ -2×10$\text{}^{21}$ cm$\text{}^{-3}$. The layers grown under the conditions of an extra Te flux have a high carrier concentration and exhibit ferromagnetic phase transition at T$\text{}_{C}$ ≤ 7 K. The layers grown with no (or very low) additional Te flux show low carrier concentrations (below 10$\text{}^{20}$ cm$\text{}^{-3}$) and remain paramagnetic in the temperature range studied T=4.5÷70 K