Magnetic core

About: Magnetic core is a research topic. Over the lifetime, 30011 publications have been published within this topic receiving 155247 citations.

Design and characterization of a microwire fluxgate magnetometer

Abstract: This paper deals with the characterization of fluxgate magnetometers that adopt a FeSiB microwire as magnetic core. The proposed device has a number of peculiarities that make this sensor very interesting. In fact this magnetometer affords the detection of weak magnetic targets with a very high spatial resolution and low power consumption. The readout strategy is based on the use of the “Residence Times Difference”; the DC magnetic field information is derived from the temporal positions of the output waveform spikes. In the paper an accurate device characterization is performed with particular regards to sensor resolution, sensitivity and power consumption; moreover, some comparisons between the FeSiB microwire fluxgate and a “ribbon” Magnetic Alloy FR4-fluxgate, previously developed by the authors, are presented. Finally exhaustive experimental characterization results demonstrate the possibility to use the microwire fluxgate as a low power system (with high spatial resolution) operating with a sinusoidal bias current of 5 mA pp .

On a circuit theory approach to evaluate the stray capacitances of two coupled inductors

Abstract: This paper provides a method for evaluating three lumped equivalent capacitances which take into account the physical effects of stray capacitances in two coupled inductors. Capacitance evaluation is performed in two steps: (i) initially, the resistance and leakage inductance of each winding, together with the magnetic core equivalent impedance, are evaluated by means of discrete parameter estimation; (ii) successively, the three equivalent capacitances are evaluated by resolving a linear set of three algebraical equations after the natural oscillation frequencies of the two coupled inductors in experimental tests are determined. The paper provides both the definitions and the mathematical theory on which the method is based. The actual response of two coupled inductors was compared with the response of the identified model; tests showed a good correlation between them. >

Shorted turn axial driver-sensor

Abstract: A pressure measuring system utilizes an aneroid capsule as the frequency determining mechanical feedback element of an electrical oscillator, the capsule having closely spaced diaphragm walls, each carrying a separate electromagnetic element cooperating with a separate magnetic yoke assembly. Each electromagnetic element is a copper sleeve defining a shorted turn at its free end that is axially movable in an annular gap defined by the magnetic yoke. Each yoke assembly includes a soft iron core section projecting through a cylindrical pole face to define a radial flux field in the annular gap for coupling with the shorted turn.

Magnetostriction and magnetic core loss at high frequency in amorphous Fe‐Nb‐Si‐B alloys

Abstract: Magnetostriction and magnetic core loss at high frequency up to 100 kHz were investigated together with crystallization temperature, saturation magnetization, and magnetic permeability for amorphous (Fe1−xNbx)zSi88−zB12 alloys. Crystallization temperature significantly rises with Nb addition, particularly in the high z region. Magnetostriction decreases with increasing Nb content and z value. Magnetic core loss decreases and magnetic permeability increases with decreasing magnetostriction. Magnetic core loss reduction due to Nb addition were analyzed to be mainly attributed to domain width reduction through the decrease of magnetostriction.

CMOS magnetic sensors with integrated ferromagnetic parts

Abstract: The paper deals with Hall and flux-gate magnetic field sensors consisting of integrated combination of CMOS ASICs and planar ferromagnetic components. Ferromagnetic parts are made of a soft amorphous alloy, integrated at the CMOS wafer in a post-processing production phase. When the sensors are exposed to an in-plane magnetic field, under the peripheries of ferromagnetic parts appears a strong magnetic induction perpendicular to the wafer surface. This perpendicular field is sensed either by Hall plates or planar coils. In the case of Hall magnetic sensors, such ferromagnetic parts give a magnetic gain of 2–10. Compared to conventional integrated Hall magnetic sensors, the new sensors have up to 10 times higher magnetic resolution and they respond to a magnetic field parallel with the surface of the chip. They are used as current sensors or angular position sensors. In the case of flux-gate sensors, both the saturation-forcing coil and the pick-up coils are realized as planar coils, using metallization layers that exist in the CMOS process. The integrated flux-gate technology is illustrated by a low-power two-axis magnetic field sensor suitable for a portable electronic compass.