SU918907A1 - Method and device for measuring pulse magnetic field amplitude - Google Patents

Description

(Sl) DEVICE FOR MEASURING THE AMPLITUDE OF A PULSE MAGNETIC FIELD AND A METHOD OF ITS IMPLEMENTING

one

The invention relates to a magnetic measuring technique and can be used to measure the amplitude of a pulsed magnetic field.

A known Hall sensor, made in the form of a dielectric-semiconductor metal (metal-semiconductor) type structure, in which the metal acts as a gate relative to the semiconductor. A change in the gate potential leads to the appearance of a thin conducting inversion layer on the sensor surface. The small thicknesses of the inversion layers cause an increase in the ratio of the EMF of Xsll and the emf of induction pickup t.

The disadvantages include the fact that the increase in measurement accuracy by the above method is limited. In addition, in order to register the maximum value of a pulsed EMF, it is necessary to create a rather complicated electronic circuit.

A known method for directly measuring a pulsed magnetic field by a Hall sensor is by detecting a pulsed Hall voltage 2.

The disadvantage of this method is a large measurement error, due to the presence of inductive emf on the output electrodes, the level of which at small pulse durations can exceed

0 value of EMF Hall. In addition, compensation for inductive pickup arising in the output circuit is difficult, due to the need to match not only the amplitude, but also the phase

15 and the frequencies of the signals, however, due to the frequency dependence of the compensation impedance of the circuit, is only feasible at fixed frequencies of the magnetic field,

Claims (2)

20 moreover, it is practically not always applicable, for example, when measuring the amplitude of single and rare repetitive pulses. With large lengths of 39 lead wires (on the order of 100 m), the areas of the induction loops are usually very large (on the order of 20-80). This leads to an increase in the level of parasitic pickup, which, for a given accuracy of compensation, is associated with an increase in the absolute level of the uncompensated part of pickup, and consequently, with a decrease in the measurement accuracy. The purpose of the invention is to improve the measurement accuracy. The goal is achieved by the fact that in a device for measuring the amplitude of a pulsed magnetic field containing a Hall sensor with current and Hall electrodes made in the form of a semiconductor plate deposited on a dielectric layer, a layer of ferromagnetic material is inserted on it . The goal is achieved according to the method implementing the device, which consists in pre-magnetising a layer of ferromagnetic material, and the Hall EMF is measured at the end of the impact of a magnetic field pulse. FIG. 1 is a schematic diagram of the structure during exposure to a magnetic field pulse with a strength in FIG. 2 - the same, after the termination of the action of this impulse; in fig. 3 a circuit for switching on a structure using an inversion semiconductor layer as the active conductive Hall plate; Fig. 4 shows the graph of the dependence of the constant Hall voltage level on the amplitude. The ferromagnet dielectric - conductor structure during a pulse of a magnetic field with amplitude H (figure 1) consists of a monocrystal semiconductor plate 1, a dielectric layer 2 (since an epitaxial layer is used as a single crystal plate, semi-insulating acts as a dielectric substrate), ferromagnetic material 3. When exposed to a pulse structure with an amplitude of intensity H in the ferromagnetic material 3, induction occurs, upon termination of the effect of the impulse The amplitude H / (the induction in the ferromagnetic material 74 3 is reduced to the value of the residual induction Wu, (Fig. 2). In the open air gap located between the poles of the magnetized ferromagnetic material, induction Bj will occur, which leads to a constant Hall EMF time and, by which the maximum amplitude of the magnetic field pulse amplitude is determined. Wiring diagram of the structure (Fig. 3) when an inversion semiconductor layer, t, e, is applied to the current The electrodes are energized, the EMF of the Hall is removed from the Hall electrodes, and a voltage bias is applied to the ferromagnetic material, the ferromagnetic material is used as a gate, the potential of which is different from the potential of the semiconductor. This method of measuring the amplitude of a pulsed magnetic field can also be used when using the sensor of ordinary single-crystal layers as an active plate of the sensor. In this case, the ferromagnetic material can be non-conductive. Ferromagnetic material is most appropriate to use in the form of a flat plate with dimensions that match the dimensions of the active plate, since the residual induction will penetrate the entire area of the active plate of the sensor. An increase in the level of the measured Hall emulsion with such a form of magnetic material can be achieved through the use of high-ersivity alloys. The creation of the metal-dielectric-semiconductor structure is carried out by known methods, for example, by sputtering a ferromagnetic alloy on an oxide insulating film deposited on the surface of a semiconductor. The choice of ferromagnetic material and its thickness is determined by the shape of the hysteresis loop necessary to enable measurement of magnetic fields in a given range. Experimental determination of the amplitude of the magnetic field is carried out according to previously removed calibration curves of the dependence of the constant Hall voltage on the amplitude, in particular (FIG.) For a magnetic field pulse with a duration t, 59 Testing the method is carried out by mounting on an epitaxial Hall sensor with the dimensions of the active region 10 X 5 A0.01 mm ferromagnetic material with dimensions of 5 liters (3-10) mm. The determination of the maximum amplitude of the pulses of a magnetic field of a rectangular and sawtooth shape by this method is carried out on Hall-type silicon wafers using Si O as a dielectric and a Cu-Mi-Co magnetically hard alloy of the Kuniko-1 type. The measurement error does not depend on the temporal parameters of the pulse for the studied durations over 10 s and is determined mainly by the accuracy of the removal of the calibration curve and f (H) equal to 0.5 in the range of 1-10 kOe. The Hall EMF is recorded by a DC voltage microvolmeter. Using the proposed method allows one to completely eliminate the measurement error associated with the presence of induction pickup and significantly simplify the registration scheme. 7 claims 1. A device for measuring the amplitude of a pulsed magnetic field containing a Hall sensor with current and Hall electrodes, made in the form of a semiconductor plate deposited on a dielectric layer, characterized in that a layer of ferromagnetic material is introduced into it on which the dielectric layer is reinforced. 2. A method that realizes the device VOP .1, characterized in that the layer of ferromagnetic material is preliminarily demagnetized, and the Hall electromotive force is measured at the end of the magnetic field pulse. Sources of information taken into account in the examination 1. Weiss G. The physics of galvanromagnetic semiconductor devices and their application. M., Energie, 197, p. 83-85. 2. Cobus L., Tushinsky I.Ya. Hall sensors and magnetoresistors. M., Energie, 1971, p. 218. FIG. / t / j.ffKS ZOOISO 10050-0 1-w Hj.Alfi 5-U J- / fig.