Papers by Keyword: Magnetic Sensor

Abstract: This paper is a comparison of the carrier deflection mechanism of a new magnetic sensor structure between the tunneling Field Effect Transistor (TFET) structure and the FinFET structures so-called MAG-TFET and MAG-FinFET.The device relies on carrier deflection from magnetically induced forces. The MAG-TFET current is caused by electron tunneling and drifting through the bulk under gate while the MAG-FinFET current is caused by the drift channel carrier from the inversion layer induced by gate voltages and there is also a bulk current beneath the substrate. The carrier deflection of the device is due to the current in the induced channel and current in the bulk. From the results, carrier deflection in the induced channel is better than in the bulk. The device sensitivity depends on the proportion of these two currents.

Abstract: This paper studies the aspect ratio (W/L), width (W) per length (L) of semiconductor resistor based on Hall effect current mode for horizontal magnetic field. At low concentration, 10¹⁴ cm^-3, W/L < 1, the length has direct effect to magnetoresistance. The W/L = 1, the large resistor provides magnetioresistance better than small device. The W/L ˃ 1, the width has inversely proportional to magnetoresistance. The %MR(B) is around 1 % at 0.5 T, 1 mA. The long resistor (W/L < 1) can create ΔR in the order of several kilo ohms and several hundred ohms for short resistor (W/L > 1). The contribution factors ρ (L/W) for high ΔR are low concentration and aspect ratio (W/L < 1). The high %MR(B) is contributed by high current density of short structure (W/L > 1). At high concentration 10¹⁷ cm^-3, aspect ratio and magnetoresistance are not sensitive to magnetic field because the Hall effect hardly occurs in high concentration material.

Abstract: This experimental research proposes a contactless silicon-based two-dimensional (2D) Hall sensor capable of simultaneous parallel-and perpendicular-directional magnetic sensing, with a 360° angle measurement. The Hall sensor was of non-symmetrical five-ohmic contact configuration (C1 – C5). In the study, experiments were carried out in three stages. In the first-stage experiment, the current (I) and voltage (V) of the 2D Hall sensor were determined under three schemes: schemes A (C1&C2), B (C2&C5), and C (C3&C4). In the second-stage experiment, the parallel and perpendicular absolute sensitivities of the 2D sensor were examined. Considering the discrepancy between the parallel and perpendicular absolute sensitivities, signal conditioning circuitry was incorporated into the sensor system to compensate, and the rotational angles measured in the final-stage experiment. The results revealed that the I-V curves were dominantly linear, corresponding to Ohm’s law. However, the parallel and perpendicular absolute sensitivities were low and unequal. Thus, signal conditioning circuitry was incorporated into the system to address the discrepancy and improve the performance. Importantly, the 2D Hall sensor exhibited a mere ±3^o discrepancy between the measured and reference rotational angles, given the magnetic flux density of 1000 G, with the hysteresis error of 2.8%. In essence, the proposed contactless silicon-based 2D Hall sensor possesses high potential for high-precision industrial applications.

Abstract: This paper presents our proposed frequency sweeping excitation and spectrogram method (FSES method) by a magnetic sensor for non-destructive testing of hardened low carbon steels. This method can evaluate the magnetic properties of low carbon steels which were changed after induction heating treatment. It was examined by our proposed method that the degrees of yield strength of low carbon steels were varied depending on hardened conditions.

Abstract: Nickel nanowires were synthesised using a template free chemical method. The phase purity and crystallinity of the synthesized nanowires were studied. Nickel nanowires with diameters of approximately 100-120 nm have exhibited a saturation magnetisation value of 51 emu/g and coercivity of 300 Oe which makes them potential candidates for magnetic sensor applications.

Abstract: Low field and room temperature operation range are two critical requirements for magnetic sensors. In this paper, nanoparticles of La_0.7Sr_0.3MnO₃ (LSMO) were elaborated to fulfill these requirements. La_0.7Sr_0.3MnO₃ nanoparticles were synthesized using sol-gel method. The physical properties of LSMO were examined by X-Ray diffraction and Scanning Electron Microscope. The ferromagnetic nature of LSMO samples was confirmed by magnetization measurements. Nanoparticles were pressed in shape of pellets and sintered at different temperatures of 900°C, 1000°C, 1100°C and 1200°C. Magnetoresistive measurements were taken at room temperature with magnetic field (μH) in range ±110 mT. The experimental results show maximum magnetoresistive ratio and sensitivity of 1.3% and 0.023%/mT respectively for sample sintered at 1000°C. Other sensor characteristics namely hysteresis error, response time and noise measurement were also given.

Abstract: Nano systems with combined magnetic and plasmonic functionalities have become an active topic of research in recent years. By an adequate internal architecture of the constituting components, the magneto-optical activity of these systems can be greatly intensified due to the electromagnetic field enhancement associated with the plasmon resonance. One of such approaches is a creating of magnetoplasmonic crystals (MPlCs) based on the noble and ferromagnetic metals. This work represents results of the investigation of the magneto-optical (MO) properties of the magnetoplasmonic structure, and parameters of the magnetic field sensor based on such structures. Possibility of creation of the magnetic field sensor with different properties is represented.

Abstract: Based on PNI11096 magnetic sensor data acquisition system can be used for path recognition of automatic guided vehicle (AGV). The use of the magnetic field on the path to produce paving soft magnetic strip, AGV at run time through the sensor detects the current relative to the magnetic field strength of soft magnetic data will be returned in the STM32 chip data processing after two values through the open collector output 16 bit IO, provide location information for AGV.

Abstract: The precision of magnetometer positioning is affected by the geomagnetic anomaly, and traditional positioning technology cannot be applied to the motion sensor positioning. A magnetometer localization method based on a variable magnetic source is proposed. The method localizes a magnetic sensor by the absolute value of the magnetic field. Positioning process does not use geomagnetic coordinates to avoid the effects of geomagnetic anomalies. The method uses time-division multiplexing technology to achieve the motion sensor positioning. Simulation results show that the average positioning error is 0.3% and the maximum positioning error is 1.3% when the tilt angle of the magnetic source is ±1 degree. It has the advantages of high precision.

Abstract: Maxwell coil cannot meet the magnetic sensor calibration when the high uniformity of magnetic gradient is required and the space size is strictly limited. To solve this problem, a magnetic gradient coil with high uniformity was designed as magnetic sensor calibration device. Application of internal series method analyzed the magnetic field that a single axial symmetric coil generated, and then got the general characteristics of the magnetic gradient field distribution. On this basis, the structural parameters and the uniformity of magnetic gradient coil with high uniformity were calculated. Simulation analyses were carried out on the coil model and complete the design and production of magnetic gradient coil device. Finally, the data obtained from actual measurement and simulation proves the correctness of the design.