SU760007A1 - Device for determining magnetic specimen anisotropy conctants - Google Patents

Description

The invention relates to devices for measuring the magnetic properties of solid materials and can be used both in laboratory studies of the anisotropy of magnetic crystals and films, as well as for controlling the quality of the texture of ferromagnetic sheet materials, such as steel.

Known torsional magnetometer for automatic recording of torque curves acting on a magnetic sample in a uniform magnetic field And ·

The object to be measured is placed at the .15 end of a vertical rigid rod suspended on an elastic thread. Torque experienced by the sample causes the rod to rotate around an axis, which is converted to 20

compensating voltage that returns the rod to its original position.

The disadvantages of the known magnetometer are the low accuracy of measurements, due, in particular, to 25 zero drift, and the lack of reliability associated with the presence of thin strands of suspension that are prone to breaks. In addition, due to the absence of an amplifier in the compensation circuit, with 3θ

measurements on this magnetometer torque in the entire working range from 10 ' ³ to 5 dyn. cm, you must replace the suspension thread, which affects the inconvenient.

A device with a rigid suspension system is known ^ 2]. The basis of the design of this device is a vertical rod supported at two points, at the lower end of which the sample under test is installed. The upper end of the rod is connected to the electro-. magnetic compensator, creating a compensating torque.

A significant disadvantage of this magnetometer is the low accuracy of measurements, due to the use of an air bearing rod as the lower support point. This design supports eliminates undesirable displacement of the sample in the horizontal plane, slightly increasing the reliability of the instrument. However, due to the turbulence of the flow, parasitic torque inevitably creates in the air bearing itself, reducing the measurement accuracy of the device. In addition, the air bearing design is thrown ¹ mozdka.

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In order to improve the accuracy of measurements, a device for determining the anisotropy of magnetic samples, containing a sensible element with a platform, reference nodes of the sensing element, a null indicator, a compensation signal setting unit 5, arayaya unit The zero point zero point compensator, output device and magnetic system are weakly weakened by two compensation springs, a torsion head, a twist angle angle scale θ, a reading unit and an adder, and the reference nodes are made in the form of two elastically deformable len t, one of which is mechanically connected with the scale of twisting angle and a tapping head, and is optically connected with the reading unit, and the second is connected to the output of the summator, while the compensation springs are located at the ends of the elastically deformable

tapes, and the inputs of the adder are connected to the block job compensation -

signal and unit set the signal to set the zero point. ·

The drawing is a diagram of the pre-C

lag device.

The device consists of a sensing element 1 with a landing pad 2 on which the anisotropic magnetic sample 3 (for example, a crystal) is fixed. Sensory-30

"Ny element 1 is installed on the reference

balancing (compensation) signal. The arreter is 36 intended In order to fix the sensitive element 1 during removal (attachment) of the platform 2c with the test sample Z. The magnetic system 37 creates a magnetic field acting on the sample 3 with intensity K.

The operation of the device is as follows.

In the initial position, in the absence of an acting magnetic field in the magnetic system 37, the zero position of the sensing element 1 is checked and, if necessary, you enter the appropriate correction signal of the zero point setting (current 3 ₀ ) from block 30.

When installing the object under study in a magnetic field created by the magnetic system 37, a magnetometric torque ΚΛχ appears, equal to 1

 (one)

where K _α .. V. ρ (nodes 4-5, supporting it and made with the possibility of rotation around the axis of sensitivity 0 ^ -0 ^.

Support assemblies 4 and 5 are resiliently deformable ribbon 6-7 together with compensating springs 8-9 'mounted under axial preload _P and the ends of resiliently deformable ribbons * 10-11 6-7.

Elastic-deformable tape 6 is equipped with a twisting head 12, a scale 13 of the twist angle>> g _P and a reading unit 14 in the form of a lamp 15, a capacitor 16, a micro-lens 17, a mirror 18 of the screen 19.

The device also contains a null indicator 20, consisting of a backlight lamp 21, a movable mirror 22, '; optical system 23 forming

The light hare 24 and the photoconverters 25. The zero indicator 20 is designed to generate an electrical signal d and _{6) ς} Β depending on the magnitude and direction of the twist angle dH * of the sensitive element 1.

The output of block 26 Tasks iompensa. signal is connected to the first

"Input 27 of the adder 28, the second input 29 of which is connected to the unit 30 for setting the zero point signal. Output 31 of the adder 28 is connected to a tape of tape 6-7 with a frame 32, which together with the magnet 33 forms a compensator 34. Output device 35 connected to block 26, serves to measure

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anisotropy constant; sample volume 3,

the function of the angle <Л between the saturation magnetization vector (applied magnetic field H) and the nearest axis of easy magnetization in the crystal. The form of the function £ (сА) depends on the symmetry of the crystal and the orientation of the field. Sensitive, element 1 is twisted at an angle, and the null indicator 20 gives the corresponding signal

which, after amplification and conversion in block 26, enters as a current through the adder 28 together with the “current Z _o (zero point setting signal) to the compensator 34, which creates an opposite direction balancing.

(2)

The value of the moment is determined by the output device 35 by the formula

(·)

where X is the device constant defined by the compensator parameters 34, ’

About - balancing current post ^for barking in the compensator 34.

When "achieving the equilibrium position" of the sensitive element 1, the anisotropy constant K $ is determined by the formula

£. I___

'·' ... ^σ 'ν · Γ (<*)' ν · (ςλ) “\ .Г (сО

9)

The axial tension on the elastic deformable ribbons 6-7 creates a 'radial rigidity at the site 2, which prevents lateral displacements

0

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sample 3 under the influence of ponderomotive lateral forces p ^.

The device is calibrated in the following order.

Sample 3 is installed on pad 2 with a known anisotropic constant of 5 tropium or another other moment sensor, for example, a torsion, creating a known value of the calibration moment M _g . This value of the MGR is balanced by twisting the tape 6 with a twisting head 12 with a reading of the angle of twist on

screen 19 ¹ "·

^ gr ^{= k} gr '^ gr' (5) and

where £ _r - elastic constant band 6; l? ”- the angle of twist of the tape 6

when balancing · Μ _Γ ρ ·

* If necessary in the future

verify calibration of the output winding 35 is made tape 6 to the desired value of the angle ^ er thereby set to _T p M and the constant k is made provorka _to the formula

(βΐ

The presence of elastically deformable tapes 30

and compensation springs installed under axial tension in the support nodes, increases the radial rigidity of the device. In addition, 'these tapes, being connected to the 35 outputs of the combiner of the compensation signals and setting the zero point, allow only two current leads to be limited, and one of the tapes is used in the device for setting 40 calibration torques.

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Claims (1)

Claim A device for determining the anisotropy constants of magnetic samples, containing a sensitive element with a platform, supporting nodes of the sensitive element, a null indicator, a reference signal compensation unit, a zero point setting signal setting unit, a compensator, an output device and a magnetic system of a magnetic sample, o l and This is due to the fact that, in order to increase accuracy, it is equipped with two compensation springs, a torsion head, a scale of the twist angle, a reading unit and an adder, and support nodes; made in the form of two elastically deformable ribbons, one of which is mechanically connected to the scale of the twist angle and torsion head, and optically connected to the reading unit, and the second is connected to the output of the adder, while the compensation springs are located at the ends of the elastically deformable tapes, and the inputs of the adder are connected to the unit the job of the compensation signal and the unit set the zero point signal.