JPS6128196B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The inventor's U.S. Pat.
The magnetic device described in No. 3820090 is a ferromagnetic wire having a core and a shell with divergent magnetism. Inventor's U.S. Patent No. 1, issued July 1, 1975
As taught in No. 3,892,118, this device is made by subjecting a wire to periodic torsional strain to distort the wire circumferentially. The wire is twisted alternately clockwise and counterclockwise while maintaining its axial tension.
As a result, the wire has a relatively hard magnetic shell and a relatively soft magnetic core, so that once the wire is magnetized, the hard magnetic shell constrains the soft magnetic core. It is believed that this can be done.

When a wire is magnetized and placed in an increasing magnetic field parallel to the axis of the wire, the external magnetic field reaches a certain boundary that suddenly restrains the core and rapidly reverses the magnetization of the core. A pick-up coil around the wire creates pulses in response to rapid changes in the direction of magnetic flux within the core. Reversal of core magnetization occurs in response to external magnetic field strengths that cross the boundary, but is substantially insensitive. That is, the magnitude of the output pulse is only very slightly dependent on the rate of change of the applied magnetic field as it passes through the boundary value.
This is to be contrasted with conventional pulse generation circuits based on soft magnetic materials, where the hysteresis loop is continuous. The output pulse amplitude (and the reciprocal of the pulse width) of conventional types of devices is substantially proportional to the time rate of change of the magnetic field as it passes through the coercive force.

Similarly, when the external magnetic field decreases and passes through the second boundary, a reverse switching of the core magnetization occurs;
A reverse pulse is generated in the pick-up coil. The pulse output is again essentially independent of the field reduction rate and only needs to pass through the switching boundary.

The magnitude of the output pulse is extremely important in determining the value of the wire and the range of commercial applications of the wire. The larger the pulse, the easier it is for the electronic circuitry coupled to the pickup coil to distinguish it from background noise. The larger the pulse amplitude, the more repeatable the output condition initiated or recorded by the input of the pulse.

Therefore, the main object of the present invention is a switching device of the kind described in the above-mentioned patent, which provides pulses with an improved signal-to-noise ratio and a larger peak amplitude in response to a boundary external magnetic field. Form,
An object of the present invention is to provide an improved switching device.

A related and further important object of the present invention is an improved wire having a switching response to boundary magnetic fields, thereby forming uniform and repeatable output pulses from a pickup coil. The purpose is to provide wires that are

The above patent describes a magnetic device that has two magnetic states: an opposite state, where the core and shell have magnetizations in opposite directions, and a co-direction state, where the core and shell have magnetizations in the same direction. are doing.

Briefly, the wire disclosed in U.S. Pat. No. 3,820,090 is a commercially available wire, for example,
It has a diameter of 0.25 mm and is made from an alloy of 48% iron and 52% nickel.

Briefly, U.S. Pat. No. 3,892,118 discloses a method for manufacturing a wire switching device using a trace amount of nickel or iron alloy, such as
It consists of using one with a diameter of 0.25 mm. The 1 meter length of this wire is stretched by 4 centimeters. The stretched wire is held under tension between two chucks, one of the wire
It is periodically rotated clockwise and counterclockwise at a rate of 0.4 revolutions per centimeter. Thus, for a length of wire of one meter, the chuck makes 40 revolutions in one direction and then 40 revolutions in the other direction. This clockwise and counterclockwise rotation is repeated 10 to 15 times. The chuck is 450 when rotation occurs.
It is supported in a machine that maintains a constant tension of gram weight. After this step, the tension is removed and
The 1 meter length of wire is cut to the desired length (usually about 1 cm to 3 cm each) for use in the various switching and pulse generation applications developed for this wire. Ru.

Some variation in the tension, the number of revolutions per meter, and the number of cycles of clockwise and counterclockwise rotation is desirable depending on the diameter of the wire, the chemical composition of the wire, and the field of application in which the wire is to be used. .

Briefly, the preferred composition for preparing a wire exhibiting these switching properties is a wire comprised of an alloy of iron, cobalt, and vanadium.
As an example, this wire is made of 52% cobalt and 10% cobalt.
of vanadium and 38% iron. Vanadium is
It is believed that the coercive force is increased without reducing the ductility required for cold working.

Furthermore, a preferred manufacturing method has been discovered for making cobalt, iron, and vanadium wires, which produces wires with fast switching effects and thus provides repeatable and uniform high power pulses in pick-up coils. It will be done. A wire approximately one-quarter millimeter (0.010 inch) in diameter and approximately 30 centimeters (12 inches) long is subjected to sufficient tension to straighten the wire without stretching it. Thereafter, the wire is stretched and subjected to torsional strain. The torsional strain is alternately clockwise and counterclockwise to provide the necessary processing to harden the wire. The torsional strain plan is asymmetric. That is, the number of rotations in each direction is not the same. At the end of the cold working operation, the wire is subjected to an aging heat treatment by having a fundamental pulse of current flow through the wire.

This results in a switching device that has the following important properties compared to the devices disclosed in the aforementioned patents: That is, in the absence of an external magnetic field, there is an automatic transition from a state in which the core and shell have magnetization in the same direction (same direction state) to a state in which the core and shell have magnetization in opposite directions (opposite direction state). This means that no target switching occurs.

Furthermore, this results in a switching device with asymmetric switching characteristics. That is, the pulse induced when the direction of magnetization of the core is switched in a first direction with respect to the shell is the same as when the direction of magnetization of the core is switched in a second direction with respect to the shell. Different from the induced pulse. More particularly, the pulse induced when the device switches from the opposite direction state to the same direction state is substantially larger than the pulse induced when the device switches from the same direction state to the reverse direction state.

The magnetic switching device thus provided performs with a large rate of change of magnetic flux and therefore with a large output pulse from the pickup coil when switching from a reverse to a same direction state.
This device is relatively insensitive to external conditions, including the nearest external magnetic field, and is therefore useful for time control, proximity detection, and encoding applications.

The wire described in the referenced patent is used in sections of about 1 to 3 cm. Each wire segment has two magnetic states when magnetized. When switching between these two magnetic states occurs, at least a portion of the magnetic flux switches direction causing the pickup coil wound around the wire to generate a pulse. The rate at which the magnetic flux switches when the wire changes state is so fast that the electrical pulses generated by the pick-up coil are approximately 20 microseconds in duration and are distinct, sharp, and usable pulses. . The switching of states is in response to an external magnetic field having an appropriate direction such that the magnetic field strength increases above a first threshold value or the magnetic field strength decreases below a second threshold value. Then, get up. Switching of the state of the wire therefore occurs in response to a boundary magnetic field applied to the wire. As a result, the magnitude of the output pulse is substantially insensitive and is only slightly affected by the rate of increase or decrease of the triggering external magnetic field. That is, at least this effect occurs when the rate of change of the magnetic field becomes extremely high. The use of this wire has the further advantage that it produces a significant and reliable output pulse without the need for an injecting electrical signal or current. Therefore, an external permanent magnet can be used as a trigger source for the magnetic field, and all that is required is:
The situation between the bistable magnetic wire and the external permanent magnet is changed to increase the external magnetic field beyond a first boundary and/or to decrease the external magnetic field below a second boundary. Even if the triggering field is generated by the current flowing in the coil around the wire as in FIG. 2, no other electrical intervention is required in the switching device.

It is believed that bistable magnetic wires operate due to the close physical relationship between a relatively hard magnetic shell and a relatively soft magnetic core. This close physical relationship is due to the fact that both the shell and the core are otherwise homogeneous wire elements. The mechanism by which this new phenomenon occurs is still under investigation.

In FIG. 1, a tenth embodiment of a magnetic wire according to the invention is shown, the wire comprising work hardened magnetic materials consisting of cobalt, iron and vanadium. The magnetic wire sections generally have a circular cross section, preferably a true circular cross section or as close to a true circular cross section as is reasonably obtainable. Approximately 0.25 mm in diameter and approximately 3 in length
Centimeter wire sections have proven convenient.

The wire was processed as described below,
A unit magnetic wire element 10 having a relatively magnetic core 11 having a relatively small coercivity and a relatively hard magnetic shell 12 having a relatively large coercivity is prepared.

The term "coercive force" is used herein in its conventional sense to indicate the amount of external magnetic field required to nullify the residual magnetism of a magnetized body of ferromagnetic material.

In FIG. 1, the relatively soft magnetic core 11 is
It is magnetically anisotropic with respect to the easy axis of magnetization that is substantially parallel to the axis of the wire. The relatively hard magnetic shell 12 is also magnetically anisotropic with respect to the easy axis of magnetization that is substantially parallel to the axis of the wire and provides remanence. The direction of magnetization of the core 11 is largely a function of the interaction with the magnetic field by the shell and also depends on the applied external magnetic field. In the state shown in FIG. 1, the residual magnetism of the core 11 is
This is opposite to the direction from the net magnetization of 2. This state is referred to herein as the reverse direction state. In this reverse state, the region wall intermediate surface 13 is connected to the core 11 and the shell 12.
determine the boundaries of The intermediate surface 13 shown in FIG. 1 is a cylindrical boundary wall 13, although the zone wall intermediate surface may occur as a fairly complex transition zone in the wire.

It has been discovered that the pulse magnitudes obtained from cobalt, iron and vanadium wires are at least an order of magnitude greater than the pulse magnitudes obtained from the nickel-iron alloys disclosed in the aforementioned patents.

A preferred composition for the wire according to the invention has a cobalt content of about 45 to 55%, an iron content of about 30 to 50%, and a vanadium content of about 4 to 14%. Commercially available alloys of cobalt, iron and vanadium that have been found suitable for practicing the present invention are available from Wilbur B. Driver Co., Inc.
From then on, the product name was Vicalloy.
available. A wire with a diameter of 0.25 mm has been used to prepare the device according to the invention. Vaikaloi wire consists of 52% cobalt, 10% vanadium and the remaining 38% mainly iron, with certain minor components including manganese and silicon in small amounts, less than half of 1% each. It is configured.

First Processing Plan A preferred work hardening plan using a 30 centimeter length of this Vaikalloy alloy with a quarter millimeter diameter consists of the following steps.

(1) The wire is stretched to its maximum value.
In FIG. 5, wire 40 is secured to chucks 42 and 44. Sufficient tension is applied to the wire via a spring-loaded reel to
To hold a wire at a length that prevents it from bending or winding without stretching the wire. The wire 40 is further subjected to a single cycle of torsional strain consisting of approximately 64 rotations counterclockwise and then approximately 48 rotations clockwise. Tension is maintained during all torsional strain steps.

(2) The wire then undergoes 171/2 cycles of 81/2 revolutions in each direction. For more details, turn 8 counterclockwise.
After making 1/2 rotation, it makes 8 1/2 rotations clockwise, forming one cycle. This cycle is repeated 17 times and then rotated 8 1/2 times counterclockwise to complete this second step. During the second step, which usually lasts 10 to 15 seconds, the 30 cm wire is slowly stretched continuously. The amount of elongation is 1%
and 2%.

(3) The final step in the work hardening scheme consists of another series of 8 1/2 revolutions, this time with an even number of cycles, performed without further elongation of the wire and maintaining wire tension. In this step, a period three to four times as long as the period performed in the second step is repeated. Approximately 60 cycles have been found to give good results.

Next, the wire is, for example, 1 cm to 3 cm long.
Divided into usable sections.

It has been found that the above-described scheme for work hardening iron, cobalt, vanadium alloy wire reliably yields the desired results. In establishing these desired results, it has been discovered that variations in the above scheme still result in wires exhibiting switching effects.

Second Treatment Plan A less preferred wire treatment plan in which this Vaikaloi wire has been found to be effective for areas where maximum time stability is not important is as follows. A length of 30 centimeters and a diameter of a quarter millimeter is used.

(1) The wire is stretched to its maximum length. The applied tension holds the wire straight at its maximum length without elongation. The wire is further subjected to a single period of torsional strain consisting of 14 rotations counterclockwise and then 12 rotations clockwise.

(2) The wire then makes 12 rotations in each direction for 120
Receive times. More specifically, one cycle consists of 12 rotations counterclockwise and 12 rotations clockwise. This cycle is repeated 120 times. During this second step of the work hardening program, the wire is continuously stretched under torsional strain. During this second step, the 30 centimeter wire is slowly and continuously stretched by approximately 3 millimeters.

(3) The final step in the work hardening plan is to maintain tension on the wire without further elongation, and to maintain the elongation imposed in the second step, making 12 rotations counterclockwise and then rotating clockwise. It consists of a series of other steps in which the cycle of 12 revolutions is repeated 20 times.

The wire is then cut into desired lengths, for example 1 to 3 centimeters.

The alloys used in both work hardening schemes are essentially the same. The alloy is first annealed to ensure a uniform starting material and also to ensure adequate ductility for work hardening programs. The wire is initially
Preferably, it is annealed to a grain structure of 10,000 grains (or more). This fine grain structure is intended to ensure the desired ductility.

The fourth step was found to be important along with both of the above plans. This fourth step is a heat treatment step. During the initial stages of the experiment, this heat treatment was carried out at approximately 320° C. for approximately 8 hours.
However, carrying out the heat treatment at approximately 300° C. for 4 hours has been found to give satisfactory results, and such a step has the advantage of speeding up the processing of the wire. It is currently preferred to heat treat the 0.25 mm wire by passing a current of 5.6 amperes through it for 120 milliseconds. Heat treatment results in a significant improvement in the output pulse. Perhaps more importantly, this heat treatment reduces the risk that the wire will change properties when exposed to high temperature environments. This fourth process of heat treatment after work hardening
This process imparts aging, which provides stability in use.

Wire Test Procedure and Results FIG. 2 shows the results for determining the output pulses obtained using a vanadium-cobalt-iron wire according to the present invention and comparing that wire with the nickel-iron wire described in the aforementioned patent. 1 schematically illustrates the test equipment used for comparison; A 60 hertz power supply is applied to transformer 20 to provide an AC signal to solenoid 22. A piece of wire 10 is placed in the center of solenoid 22 and a pick-up coil 24 is wound around conductor wire 10. The current flowing through the windings of solenoid 22 creates an axial magnetic field at the center of solenoid 22 .

It has been found that the most pronounced output pulses are obtained from the vanadium-cobalt-iron wire when the wire is switched asymmetrically. By the circuit of FIG. 2, the excitation field H applied to the wire 10 is
This is represented by curve 32 in the figure. diode 28
passes the entire positive half cycle of the 60 Hertz AC signal, and resistor 26 is adjusted to pass a sufficiently small negative half cycle so that the excitation field applied to wire 10 has a small negative peak of 150 Oersted. We are trying to have the following.

The hysteresis loop when the wire 10 of the present invention is energized as described above is shown by curve 34 in FIG. FIG. 3 is basically illustrated in the form as it appears on an oscilloscope. The Wiegand jumps in curve 34 are named ``reverse core switching'' and ``confluent core switching.'' ) appears on the oscilloscope as an extremely weak trace. This is because the rate of change of the magnetic flux (or magnetization B) through the core 10 is extremely fast when the strength of the external magnetic field H passes through the corresponding boundary value. curve 34
, the larger interval is the part named "core switching in the same direction". In this state, due to the applied external longitudinal magnetic field H, the longitudinal magnetization of the core is changed so that the direction of the magnetization of the core is the same as that of the shell.
This occurs when the magnetization is switched from the opposite direction state (Figure 1), where the direction of magnetization is opposite to that of the core, to the same direction state, where the direction of magnetization in the core is the same as the direction of magnetization in the shell. . During "reverse core switching", the core is switched by the magnetic field H from the same direction state to the opposite direction state. As shown in FIG. 3, the pulse C induced in the coil 24 when switching from the opposite direction state to the same direction state is greater than the pulse R induced when switching from the same direction state to the reverse direction state. much larger. The pulse C induced by a core switch in the same direction has an amplitude approximately 10 times that of the pulse R induced by a core switch in the opposite direction.

More specifically, when a wire 10 with a length of 3 cm and a pick-up coil 24 with a wire size of 38 and a number of turns of 925 are used, and the output of the coil 24 is applied to a load of 1000 ohms, the pulse C is 1.5 volts or more. and has a width of approximately 20 microseconds at half amplitude. In contrast, pulse R is 125 millivolts and has a width of at least 60 microseconds. Therefore, under these conditions, the amplitude of pulse C is 12 times the amplitude of pulse R. In the case of an open circuit, a pulse C of more than 2 volts was obtained.

Interestingly, if the drive applies a positive magnetic field H of 150 Oersted along with a negative magnetic field H of 150 Oersted, two pulses 40 of equal magnitude and opposite direction (FIG. 4) are produced.
is formed. In the particular embodiment above,
Each of these two pulses 40 has an amplitude of approximately 550 millivolts and a width of approximately 40 microseconds at half amplitude.

Therefore, if the switching is symmetrical, the formed 2
The two core switching pulses are equal in magnitude to each other, their magnitude is substantially smaller than the magnitude of the core switching pulse C in the same direction obtained by optimal asymmetrical switching, and is substantially larger than the magnitude of the reversely directed core switching pulse R obtained at . This situation is illustrated in FIG. Exactly the same configuration as described above in FIG. 2, except that diode 28 and resistor 26
By using a completely sinusoidal excitation field 36, a positive
Apply an external magnetic field H whose strength repeats from 150 Oersted to -150 Oersted. As a result, a hysteresis curve 37 is obtained.

In a sufficiently positive magnetic field H, the shell 12 and the core 1
1 are both magnetized in the positive direction, as represented in the upper right corner of the hysteresis curve 37. This condition is considered a positive co-directional condition. When the external magnetic field H is reduced so that the magnetization B is reduced to a relatively small negative magnetic field H of about -12 Oersted, the core 11 switches its direction of magnetization from positive to negative. Thus, the device 10 switches from the same direction state to the opposite direction state. This creates a discontinuity point 37a in curve 37, resulting in an output pulse from pickup coil 24 at approximately 550 milvolts and having a width of 40 microseconds. Magnetization H
As the value increases in the negative direction, the direction of magnetization of the shell is switched, a point is reached where a small break point 37b is formed in the hysteresis curve 37, and a small output pulse 42 is formed. The core and shell are thus in a negative co-directional state. The magnetic field H goes to a negative peak and then returns to a smaller negative field. When the magnetic field H becomes slightly positive (approximately 12 oersted), the direction of magnetization of the core 11 is switched to the positive direction, as indicated by the point 37c. This produces another output pulse 40 with an amplitude of 550 millivolts and a width of 40 microseconds. This is a switch from a negative co-direction state to a reverse-direction state. magnetic field H
is further positive until reaching a point, represented by small break point 37d, at which the shell switches direction of magnetization to form a small output pulse 42, returning device 10 to a positive, co-directional state. continue to be.

When the applied excitation field H becomes sufficiently negative or sufficiently positive to switch the state of the shell, as shown in Figure 4, the device is switched from its co-directed state to its opposite state. At this time, a change in the state of the core always occurs. On the other hand, if the excitation field H is limited to one direction and the direction of magnetization of the shell does not switch, as shown in Figure 3, the device will switch from its same direction state to its opposite direction state. There is an asymmetric switching in that there is a core switch to , and a core switch in the same direction where the device switches from its opposite state to the same direction state. Switching from a reverse state to a co-direction state provides a larger output pulse than switching from a co-direction state to a reverse state. This is because switching from an opposite direction state to a same direction state occurs faster than switching from a same direction state to a reverse direction state.

In the embodiment described above, in order to switch the direction of magnetization of the core, it is necessary to reverse the direction of the excitation field H. Simply removing the entire driving magnetic field H will not be able to reverse the direction of magnetization of the core 11. Reversing the driving magnetic field to reverse the magnetization of the core means that the switching mode is
It may be asymmetrical as shown in FIG. 3 or symmetrical as shown in FIG. 4.

In contrast, in the nickel-iron wire embodiment disclosed in the above-mentioned patent, removal of the excitation field causes switching from the same-direction state to the opposite-direction state. Furthermore, when compared to the iron-nickel wire disclosed in the aforementioned patent, the maximum output pulse magnitude that can be obtained with the use of the iron-cobalt-vanadium wire according to the present invention is lower for the same pick-up at the same loading conditions. Using coil 24, it is approximately 10 times the size obtained using the nickel-iron wire disclosed in the aforementioned patent.

FIG. 5 is a mechanical schematic diagram showing one mechanism used for cold working wire. The length of the wire 40, for example 30 cm, is pulled by a spring-loaded reel 46. The tension is therefore 40
is given so that it remains straight. Conductor 40 is fed through chuck 42 to chuck 44. Chucks 42, 44 are then tightened to hold the wire in place. A periodic torsional strain is then applied to the wire 40 by rotating the pinion 48 on the toothed rod 50 alternately from side to side. The tooth rod 50 is a plate 5 driven by a motor 54.
2, so it moves back and forth. Extension of the wire 40 is effected by the slow rotation of a cam 56 which is pressed against an ear 58 on the chuck 42. The cam 56 is rotated by a motor drive 60.

Although wires of specific lengths and diameters are disclosed in the examples, there is no inherent reason for the invention to be limited to these specific lengths or diameters. There is a wide range of wire segment lengths and diameters that can be employed as switching devices, and the limits of that range have not yet been determined. However, in order to be able to obtain the switching effect shown in FIG. 3, it appears that the wire segment 10 still requires an undetermined minimum length. If switching from the same direction state to the opposite state occurs automatically by removal of the external magnetic field H, then the core switching pulse C in the same direction (when switching from the opposite state to the same direction state) It is thought that the amplitude of is not that large.

[Brief explanation of the drawing]

FIG. 1 is an enlarged schematic view including a longitudinal view and an end view of a ferromagnetic wire of the present invention produced by the method of the present invention, in which the magnetization of the shell portion and the core portion are in opposite directions. Figure 2 shows a solenoid actuator for applying an external magnetic field to the magnetic wire of Figure 1 and a magnetization of the shell and core in response to switching the magnetic state of the wire. A schematic diagram showing the pickup coil used to provide the output pulses; FIG. 3 is a graph of an asymmetric switching mode for switching the state of the wire, using substantially the configuration of FIG. 2; FIG. 4 shows the external drive field, the hysteresis loop and the resulting output pulses obtained from the test; FIG. Graph of Switching Modes, FIG. 5 is a perspective view displaying a technique for processing magnetic wire to provide a device of the present invention. 10...wire, 11...heart, 12...shell,
13...Magnetic intermediate plane, 20...Transformer, 22...
...Solenoid, 24...Pickup coil, 3
4a... Core switching in the same direction, 34b... Core switching in the opposite direction.

Claims (1)

[Scope of Claims] 1. A unit magnetic device having a first magnetic part and a second magnetic part, both of which remain stable even after being placed in a magnetic field. , and the residual magnetic force of the first magnetic portion is substantially greater than the residual magnetic force of the second magnetic portion, and the residual magnetic force of the first magnetic portion and the magnetic portion of the first magnetic portion are substantially larger than the residual magnetic force of the second magnetic portion. the two magnetic portions have substantially the same chemical alloying composition, and the device is in an opposite state in which the first magnetic portion and the second magnetic portion have opposite magnetizations. and the first magnetic part and the second magnetic part.
have a co-directional state in which the magnetic portions have magnetization in the same direction, and the first magnetic portion and the second magnetic portion are separated by a magnetic intermediate plane when in the opposite-direction state. When the devices are in the co-directional state, the first
the second magnetic portion such that the magnetization of the magnetic portion of the second
A unit magnetic device characterized in that a magnetic portion of the unit has a sufficiently large coercive force. 2. When the unit magnetic device is in the said co-directional state, said first
Claim 1, wherein the magnetic properties of the magnetic portion and the second magnetic portion are relatively defined.
Devices listed in section. 3. said first magnetic field such that switching of said device from said opposite direction state to said same direction state is substantially faster than said switching of said device from said same direction state to said opposite direction state. 3. A device according to claim 1 or 2, wherein the magnetic properties of the target portion and the second magnetic portion are relatively defined. 4. The aforementioned chemical alloy components have a substantial weight percent of iron, a significant weight percent of cobalt, and a significant weight percent of vanadium, where the iron and cobalt together form the alloy. A device according to claim 1, 2 or 3, which accounts for 80% or more of the weight of the device. 5. The aforementioned alloy components are between 45% and 55% cobalt, between 30% and 50% iron and between 4% and 14% vanadium, claims 1 and 2.
4. The device according to paragraph 3, paragraph 4. 6 The aforementioned alloy components are approximately 52% cobalt,
6. The device of claim 5, wherein 10% vanadium and the remainder primarily iron. 7. The unit magnetic device is a wire, and the above-mentioned first
The magnetic part of is the shell part of the wire, and the magnetic part of
6. A device according to any one of claims 1 to 5, wherein the magnetic part of the wire is the core of the wire. 8. A unit magnetic device having a first magnetic part and a second magnetic part, both of which retain residual magnetism even after being placed in a magnetic field. and the residual magnetic force of the first magnetic portion is substantially greater than the residual magnetic force of the second magnetic portion, and the first magnetic portion and the second magnetic portion are have substantially the same chemical alloying composition, and the device has an opposite orientation state in which the first magnetic portion and the second magnetic portion have opposite magnetizations; magnetic part and second
have a co-directional state in which the magnetic portions have magnetization in the same direction, and the first magnetic portion and the second magnetic portion are separated by a magnetic intermediate plane when in the opposite-direction state. separately separated and such that when the devices are in the same orientation state, the magnetization of the first magnetic portion is insufficient to switch the device to the opposite orientation state; A method for manufacturing a unit magnetic device in which the second magnetic portion has a sufficiently large coercive force, the unit magnetic device being a wire, the method comprising applying tension to the wire to form a wire of a predetermined length. holding the wire, and applying periodic torsional strain while applying tension to the wire,
the net torsional strain in one direction being substantially greater than the net torsional strain in the other direction. 9. The method of claim 8, further comprising the step of annealing said wire prior to said step of applying cyclic torsional strain. 10. The method of claim 8, further comprising the step of heat treating said wire after said step of applying cyclic torsional strain. 11. The method of claim 10, further comprising the step of heat treating said wire after said step of applying cyclic torsional strain. 12. further comprising stretching said wire between approximately 1 percent and 2 percent during said step of applying torsional strain;
The method according to claim 8. 13. The method of claim 12, wherein said step of applying torsional strain comprises approximately 30 to 120 cycles of approximately 8 to 12 torsional strain cycles per 30 centimeters of length. 14. During the said step of applying torsional strain, said wire is elongated for one part of said step, and the length of said wire is kept constant for other parts of said step. , the method according to claim 13. 15. The wire employed in the step of tensioning and holding the wire at a predetermined length has particles having an average size of approximately 10,000 particles per square millimeter. Claims 8, 9, 10, and 11
The method according to paragraph 1, paragraph 12, paragraph 13 or paragraph 14. 16. A unit magnetic device having a first magnetic part and a second magnetic part, both of which retain residual magnetism after being placed in a magnetic field. and the residual magnetic force of the first magnetic portion is substantially greater than the residual magnetic force of the second magnetic portion, and the first magnetic portion and the second magnetic portion are have substantially the same chemical alloying composition, and the device has an opposite orientation state in which the first magnetic portion and the second magnetic portion have opposite magnetizations; When the magnetic part and the second magnetic part have the same direction state with magnetization in the same direction, and the first magnetic part and the second magnetic part are in the opposite direction state, separately separated by a magnetic intermediate plane, and when the devices are in the co-directional state, the magnetization of the first magnetic portion is in order to switch the devices to the opposite-directional state. In a unit magnetic device in which the second magnetic portion has a sufficiently large coercive force so that the coercivity is insufficient, the unit magnetic device is a wire, the unit magnetic device comprising a substantial proportion of cobalt, vanadium and applying tension to the wire, which is an alloy with iron, to hold the wire at a predetermined length, and the net torsional strain in one direction being substantially greater than the net torsional strain in the other direction; applying at least one period of an asymmetrical torsional strain to the wire having a length of approximately 2 revolutions per centimeter; and applying a symmetrical and periodic torsional strain to the wire, the symmetrical strain A method for producing a unitary magnetic wire device, comprising steps substantially less than one revolution per centimeter, the number of symmetrical periods being substantially greater than the number of asymmetrical periods. 17. The method of claim 16, further comprising the step of elongating the wire between approximately 1 percent and 2 percent during one of the aforementioned steps of applying torsional strain. 18. The method of claim 17 further comprising the step of heat treating said wire after said step of applying cyclic torsional strain. 19 The aforementioned wire employed in the aforementioned step of tensioning and holding the wire to a predetermined length of wire has particles having an average size of approximately 10,000 particles per cubic millimeter. A method according to claim 16, 17 or 18.