SU1583893A1 - Pickup for measuring permanent magnetic field - Google Patents

Abstract

The invention relates to the field of magnetic measurements and can be used to measure constant magnetic fields. A sensor for measuring a constant magnetic field contains a uniaxial magnetic film with a linear strip domain structure, an inductance coil wound around it, the axis of which is perpendicular to the plane of the ferromagnetic film. The sensor is connected to a measuring device with a coaxial line with centering teflon washers. The description of the invention provides a structural diagram of a device for measuring a constant magnetic field according to a nuclear magnetic resonance method using the proposed sensor. 2 Il.

Description

The invention relates to the field of magnetic measurements and can be used to measure constant magnetic fields.

Figure 1 shows the mutual arrangement of the working substance — a uniaxial ferromagnetic film and an external constant magnetic field (a) to be measured (a) and the design of the proposed sensor (b); Fig. 2 is a block diagram of a device for measuring a constant magnetic field by the method of nuclear magnetic resonance using the proposed sensor.

The magnetic field sensor (figure 1) contains a uniaxial magnetic film 1 with a linear strip domain structure, the inductor 2 wound on it, and the axis of the coil

inductance must be perpendicular to the plane 3 of the ferromagnetic film. The sensor is connected to the measuring device by a coaxial line 4 with centering teflon washers 5. The device for measuring a constant magnetic field (Fig. 2) contains a magnetic field sensor consisting of a magnetically single-film film wound on it by an inductance coil 2, which is part of the high-frequency circuit autodyne generator 6, controlled capacitor 7; the high-frequency output of the high-frequency generator 6 is connected to the frequency meter 8. The recording device 9- through the synchronous detector 10 is connected to the low-frequency output of the generator 6, the second input of the synchronous detector 10 is connected to the first output

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generator 11 of modulation, the second output of which is connected to the first input of a controlled capacitor 7 of a high-frequency autodyne generator 6.

A magnetic field sensor is placed in a measurable magnetic field, and the lines of force of the measured magnetic field must be directed in the plane of a magnetically uniaxial film (Fig. 16) parallel to the domain boundaries. The magnetic field changes the resonance frequency of the domain boundaries and 10 A signal is received at the controlled capacitor 7. Due to a change in the capacitor of the oscillating circuit, the frequency of the oscillations generated by the autodyne generator 6 changes, approaching the value at which the resonance signal s arises at boundaries passage modulation voltage through zero. Resonance frequency domain boundaries is determined by the frequency counter 8. The magnitude of the magnetic regiment constant determined by calibration curve.

A device for measuring a constant magnetic field operates as follows.

In the coil 2 of the inductance of the circuit of the high-frequency autodyne generator 6, a high-frequency magnetic field is excited, which acts on the magnetically uniaxial film 1. When the frequency of the high-frequency auto-generator 6 coincides with the resonance frequency of the domain boundaries of the film 1, the energy of the high-frequency magnetic field is absorbed by the material. This energy absorption, equivalent to a decrease in the quality factor of the inductance coil 2 and, consequently, the equivalent resistance of the oscillating circuit of the autodyne generator 6 of high frequency, causes a decrease in the amplitude of the generated oscillations. The low-frequency voltage from the modulation generator 11 through a controlled capacitor 7 of the autodyne high frequency generator modulates in amplitude the high frequency signal at the moment of resonance. The modulated high frequency signal is detected by the autodyne generator 6 of the high frequency and the low frequency AC signal (resonance signal of the domain boundaries) is amplified by a synchronous detector 10 tuned to the modulation frequency.

Claims (1)

Invention Formula A sensor for measuring a constant magnetic field containing a core and an inductance wound on it, characterized in that, in order to increase the sensitivity of the sensor, the core is made in the form of a uniaxial ferromagnetic film with a linear strip domain structure parallel to the direction of the magnetic field being measured, and the axis of the inductor is perpendicular to the film plane. t / l / JM 1 Editor A. Kozoriz Compiled by A. Romanov Tehred L. Serdyukova Proofreader T. Paliy Order 2253 Circulation 572 VNIIPI State Committee for Inventions and Discoveries at the State Committee on Science and Technology of the USSR 113035, Moscow, Zh-35, Raushsk nab. 4/5 Production and Publishing Combine Patent, Uzhgorod, st. Gagarin, 101 FIG. 2 Subscription