JPS62159313A - Magnetic memory - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention comprises a thin film magnetic head constructed in layers on a non-magnetic substrate, and a material having a predetermined coercive force. It has a recording medium provided with a magnetizable storage film on which information is written by perpendicular magnetization, and the magnetic head has a ring head-shaped magnetic conductor that guides magnetic flux, and this magnetic conductor having two magnetic legs, each of the two magnetic legs having at least one magnetic film having predetermined magnetic properties;

The magnetic poles of the two magnetic legs pointing toward the recording medium are arranged one after the other, viewed in the direction of (relative) movement of the head, with a gap of a predetermined width being formed. The invention also relates to a magnetic storage device in which the two magnetic legs define an intermediate space outside the magnetic pole range, through which the windings of the write and/or read coil extend.

A magnetic head of such a storage device is shown, for example, in European Patent No. 0012912. With this head, information can be stored by means of perpendicular magnetization of the corresponding recording medium. This principle is generally known (for example, ``Proceedings of the Institute of Electrical and Electronics Engineers, Proceedings of Magnetic Engineering,'' Vol.
(See Vol. G-16, No. 1, January 1980, pages 71-76 or MAG-20, No. 5, September 1984, pp. 657-662 and 675-680). The storage medium used for this principle, often referred to as perpendicular magnetization, may be in the form of a magnetic storage hard disk or a flexible discrete disk (floppy disk). Each of these media has a magnetizable storage film of a predetermined thickness made of a magnetically anisotropic material, in particular a CoCr alloy, with a predetermined coercivity. The so-called easy axis of magnetization of this film is then oriented perpendicular to the surface of the medium. By means of a special magnetic head, individual information can be written as bits in successive sections along the track by corresponding magnetization of the storage film.

However, the combined write and read magnetic heads known for the principle of so-called longitudinal magnetization cannot be easily realized for perpendicular magnetization. When using this head, in which the conductive body formed from the magnetic legs generally has a ring-head-like form, it is true that the magnetic flux guiding into the as closed loop as possible, which is also desired in the principle of perpendicular magnetization, is slight. This can be achieved with magnetoresistive. However, the bit density is high,
It is therefore difficult to generate a sufficiently high write field if the length of the so-called air gap formed between the magnetic poles of the ring head facing the recording medium is correspondingly small.

Therefore, it is necessary to develop a special write/Vt output magnetic head based on the principle of perpendicular magnetization. Such a head construction is shown, for example, in the European patent mentioned above. This known magnetic head has a so-called magnetic conductor for guiding the magnetic flux.

This magnetic conductor is formed by two magnetic legs each consisting of a membrane of a magnetic material with predetermined special magnetic properties, for example a special NiFe alloy (for example "Permalloy", a registered trademark of the Bell Telephone Manufacturing Company). be done. Its end region facing the recording medium forms two magnetic poles which are arranged one after the other at a predetermined small distance from each other in the direction of movement of the head. These end regions are followed by a head region in which the magnetic legs are guided at a greater distance from each other. A sufficiently large intermediate space is thus obtained between the two magnetic legs, through which the windings of the write and read coils extend.

For both the write function and the read function, a ring head-like configuration of the magnetic conductor with both magnetic legs is used.

The individual parts of this known magnetic head are attached to the flat back side of a non-magnetic substrate. This technique is generally known (e.g. "Precision Mechanisms and Measuring Technology (Fei)
nwerktechnik und Messtech
Nik), Volume 88, No. 2, March 1980, No. 5
Pages 3-59 or “Siemens Zeitschrift (S
iemens Zeitschrift) J, No. 52
Vol. 7, 1978, pp. 434-437).

However, such a thin film magnetic head has a problem in generating a sufficiently large write magnetic field while maintaining high resolution during reading. Both of these requirements are contradictory to each other. That is, in general high magnetic fields can only be achieved with large gap widths and/or large pole thicknesses, whereas high resolution at high bit densities is achieved with small gap widths and/or large pole thicknesses.
or) achieved only by small pole thicknesses (e.g., Proceedings of the Institute of Electrical and Electronics Engineers, Proceedings of Magnetic Engineering, Vol. MAG
-Volume 19, No. 5, September 1983, Nos. 1617-16
(See page 19). Furthermore, in a magnetic head for perpendicular recording, the write field has a possible It must be asymmetrical to the extent possible. However, in known magnetic head types, the magnetic field at the trailing edge is generally somewhat weaker than the magnetic field at the leading edge.

[Problem that the invention seeks to solve]

It is therefore an object of the present invention to improve a magnetic storage device of the f class mentioned at the outset, in such a way that its magnetic head allows writing and reading functions, respectively, with relatively high efficiency, according to the principle of perpendicular magnetization. It is. In this case, the above-mentioned requirements regarding large write fields and high resolution must at least be taken into account.

[Means for solving problems]

This object, according to the invention, provides that at least one magnetic membrane of a subsequent magnetic leg, viewed in the direction of movement, outstrips at least its magnetic pole of a preceding magnetic leg with respect to its magnetic properties at least in the end region constituting its magnetic pole. The coercive force of the material of the storage film of the recording medium is selected to be sufficiently high, so that the coercive force of the material of the storage film of the recording medium is selected to be sufficiently high, so that the magnetic pole of the subsequent magnetic leg is This is achieved in that overwriting of the storage medium by magnetic fields is at least largely eliminated.

As a characteristic magnetic property of each magnetic film, it is advantageous to pay particular attention to the magnetoresistance of the film or the saturation magnetization of the film material, at least within the end range constituting the magnetic pole.

Advantageous embodiments of the magnetic storage device according to the invention are listed in the subclaims.

〔Effect of the invention〕

A particular advantage of the magnetic storage device according to the invention is that during writing, the magnetization of the magnetic film of the succeeding magnetic leg is lowered in its magnetic pole range compared to the magnetization of the magnetic film of the preceding magnetic leg; This consists in that the vertical component of the magnetic field of the magnetic leg is correspondingly smaller than the vertical magnetic field of the preceding magnetic leg. This means that the magnetic head writes with a very steep slope between the magnetic fields forming the two magnetic poles. As a result, the magnetic transition length, which is important for the read amplitude, is also strongly shortened by the running edge compared to normal writing. That is, the magnetic head of the magnetic storage device according to the invention differs from known heads in that it writes with its leading magnetic pole due to the different magnetic properties of its magnetic legs. This is ensured, in particular, by selecting a material with a high value of the (perpendicular) coercive force for the storage film of the recording medium, such that the magnetic field of the passing magnetic pole is no longer sufficient to write into this storage film. can be done.

On the other hand, magnetic heads operate on the basis of weaker magnetic fields during reading, as is the case with conventional thin-film ring heads, which record very sharp magnetic transitions with correspondingly large successive voltages. Furthermore, it is particularly advantageous that the gap width in the magnetic head of the storage device according to the invention can be kept very small with little loss of the writing properties, and that the maximum achievable bit density is thereby correspondingly large.

〔Example〕

The present invention will be described below with reference to the drawings.

In a first embodiment of the magnetic recording device according to the invention, which is shown in partial longitudinal section in FIG. Starting from the known ring-head-shaped embodiment (
see for example the European patent mentioned above). A magnetic head, generally designated I, performs both the writing and reading functions. This head rests on the flat side of a non-magnetic substrate (not shown in the drawings) which forms the front or in particular the rear side of the element, also called a conventional levitator. The magnetic head itself is maintained at a small flying height f relative to the known recording medium A, and the direction of movement of the recording medium relative to the magnetic head is indicated by the arrow marked V. It is shown. Flying height f maintained between the lower surface of head 1 facing recording medium A and recording medium A
is only on the order of 0.1 μm. A recording medium A, for example a magnetic storage disk, has a storage film 6 that is vertically oriented and has a predetermined thickness D. The material of the memory film, such as a CoCr alloy, is 20 kA/m, for example.
, preferably greater than 60 kA/m (
perpendicular) should have a high value of coercive force H0 (see EP 0120413 and EP0054269).

The memory film 6 is made of a special NiFe film, for example, which optionally also has a ternary additive of Ni or Nb.
Advantageously, it is arranged on at least one further soft magnetic film of alloyed or amorphous CoZr or CoHf. This inferior membrane is designated by the reference numeral 7 in the drawings.

The main magnetic head has two magnetic legs i and y, and a ring head-shaped magnetic conductive weight that guides magnetic flux. These magnetic legs generally and specifically point the magnetic pole M towards the recording medium.
In the end region 11 or 12 constituting pl or Mp2 it is oriented at least approximately perpendicular to the surface of the recording medium.

End regions here each mean a thin end piece of the magnetic leg that has an at least approximately uniform thickness or is not reinforced by another membrane. The end ranges 11 and 12 are magnetic poles Mp
l and Mp2 smaller than 1 μm, especially 0
．． They are spatially separated by an air gap 13 having a width g in the longitudinal direction, ie in the direction of movement V of the magnetic head, of less than 5 μm, preferably less than 0.25 μm. In the central region of the conducting mass, the spacing between the two magnetic legs and 10 is such that, for example, the direction opposite to the direction of movement V is such that the subsequent magnetic legs are configured flat on the front side (facing towards the substrate 3). ) By having a larger width W for the magnetic pedestal, it is widened compared to the above gap width g. Outside this region 15, on the side of the conductive mass facing away from the recording medium A, the magnetic leg IQ- is attached in a known manner to the magnetic field 11111 in the connecting region 16, so that the conductive mass A ring head-like morphology has occurred.

Through an intermediate space 17 formed in the central region 15 between the two magnetic legs and 10 extends at least one flat coil winding 18 which can serve both as a write coil and as a read coil. There is. A single layer 18a is shown in the drawing.
The windings only shown can be constructed in multiple layers and generally have a relatively large number of turns. A relatively large write current 1 flows through it.

Both magnetic legs of the magnetic head 1 and 10 each have a film thickness d1.
or d2, it is constituted by at least one magnetic film 9a or 10a. Here, each film thickness is the respective magnetic pole range 11 or 1 seen in the direction of motion V.
2 means the corresponding membrane thickness. Now, according to the invention, these magnetic membranes should have different magnetic reluctances at least in their magnetic pole ranges 11 and 12, with the membrane 10a of the subsequent magnetic leg 10 having a much higher magnetic reluctance in the direction of movement. It should have a high magnetoresistance RM2, preferably by a factor of two. Compared to that, the leading magnetic leg 1 is lower.
The magnetoresistance of 99a is given in RMI. As is well known, the magnitude of the magnetic resistance of each magnetic film is related to the reversible magnetic permeability μr and geometry of the respective magnetic film. The reversible magnetic permeability of the magnetic film can be determined by the material selection and, for example, by the manufacturing conditions during sputtering. Preferably, a material having a reversible magnetic permeability μr1 larger than the reversible magnetic permeability μr2 of the magnetic film 10a of the succeeding magnetic leg is selected for the magnetic film 9a of the preceding magnetic leg.

The larger reversible permeability μr should then have a value of more than 1 month 000, preferably more than 3000, while the smaller reversible permeability μr2 should generally have a value less than 1000, for example about 500. It is. Preferably, materials are selected whose reversible magnetic permeabilities differ by a factor of at least three.

Furthermore, the film thicknesses d1 and d2 of the magnetic films 9a and 10a are
By adaptive selection of the magnetic films, the magnetoresistance of these magnetic films can be changed. The thickness of these films is less than 2 μm, especially 1 μm.
It should be chosen to be smaller than μm, preferably smaller than 0.7 μm.

In some cases, at that time, the magnetic film 9a of the preceding magnetic leg
, a value of the thickness dl is selected that is larger than the value of the thickness d2 of the magnetic film 10a of the succeeding magnetic leg 10. 30KPC
I (kilo Flux Change p
For bit densities exceeding er Inch), for example dl < 0.6 μm, d2 < 0.4 μm or g <
It should be selected to be 0.25 μm.

In this case, the flying height f and the thickness D of the CoCr storage film should satisfy the inequality f+D<0.5 μm. Furthermore, the thickness of the soft magnetic underlayer should not be significantly less than the thickness of the thicker of the two magnetic poles Mp1, Mp2.

Furthermore, as can be seen from FIG. 1, each of the magnetic legs and 10 may be provided with an additional relatively thick magnetic film 9b and 10b outside the respective end area 11 or 12, with these The membrane in particular covers the central region 15 of the conductive mass with the coil winding 18 . The thickness of these additional magnetic films 9b and tab is indicated by d3 or d4.

Magnetic Ill! 9b and 10b are respective magnetic poles Mpl
Alternatively, it does not reach Mp2 and terminates at a predetermined distance from there. In this way, the magnetic films 9b and tab define the upper limit of the end range 11 or 12. The end region 12 of the magnetic leg 10 thus begins at the point where the outside of the magnetic film 10b, marked 20, abuts the outside of the magnetic film 10a. Furthermore, as indicated by broken lines 20' and 20# in the drawing, the outside of the magnetic IQ 10b terminates at a further recessed point, so that the end range of the magnetic film 10a is correspondingly widened. outside 20'
or these end ranges delimited by 20" are coded 1
2' or 12''.

The additional magnetic films 9b and 10b serve to advantageously influence the reluctance of the respective magnetic leg and can further be utilized to asymmetric the magnetic field distribution of the write field as desired. Thus, the different lengths of the outer sides 20, 20', 20' or the different extents of the magnetic film 10b with respect to the recording medium A have a strong influence on the write/sequence characteristics of the magnetic head 1. Thus, for example, shorter magnetic legs lead to better write fields, but smaller read amplitudes.

As another method for increasing the magnetic resistance of the subsequent magnetic leg 10, a reduced cross-section portion that increases magnetic resistance is formed in the magnetic film 10a.
It can also be provided inside. This cross-sectional reduction can preferably be located at the edge of the end region 12 or 12' or 12'' facing the central region 15. According to the embodiment shown, such a resistance increase This can be obtained, for example, by over-etching an etching recess in the magnetic film 10a constituting the magnetic pole Mp2 of the magnetic leg during ion beam etching of the magnetic leg 10.The outline of this etching recess is shown in the drawing. Broken line 22
It is shown by.

The saturation characteristics of the end ranges 11 and 12 or 12', 121 of the magnetic pedestal or 10 with magnetic poles Mpl and Mp2, and therefore also the magnetic field that can be generated/followed by the coil 1
The position of 8 also has an influence. That is, the closer this coil is located to the gap 13, the greater the magnetic field. However, it should be taken into account that due to this proximity, the desired asymmetry of the magnetic field distribution is partially regressed. The position of the write/sequence coil 18 thus provides another possibility of influencing both the amplitude and the asymmetry of the magnetic field.

The material of the magnetic films 9a, 9b and 10a, job is in particular a FeNi alloy such as "permalloy" or an amorphous CoZr or CoHf alloy. Optionally, further, for example ternary, partners may be added to the alloying partners of these amorphous alloys.

In this way, due to the different reluctance ratios to be set in both magnetic legs and 10, in particular in their respective end regions 11 or 12, 12', 12', the magnetic pole M of the preceding magnetic leg
The write function can be performed only by pl. In order to ensure this characteristic mode of action of the magnetic spatula 1, i.e. to avoid, at least approximately, that the information written by a preceding magnetic leg maker is overwritten by a subsequent magnetic leg 10, In the magnetic storage device according to the invention, the coercive force Hc of the storage film 6 on the recording medium is further selected to a height such that the magnetic field of the running magnetic pole Mp2 is no longer sufficient to rewrite the written information by switching magnetization. There is. The corresponding magnetic field ratios are shown in more detail in FIG.

In this case, the absolute value of the coercive force H0 is, for example, at least 20
kA/m, preferably at least 60 kA/m.

In FIG. 2, the strength H of the magnetic field generated by the magnetic poles Mpl and Mp2 is shown in relation to the extent X in the direction of movement V of the magnetic head. In FIG. 2, the contours of these magnetic poles are shown only schematically and not to scale. The magnetic field strength H plotted on the vertical axis is measured in the vertical direction (y direction) on the surface of the recording medium A. As can be seen from FIG.
Has SI. This maximum is clearly due to the corresponding (
The positive) switching field “+Hc” is exceeded. Here, this switching magnetic field “+Hc°” indicated by a broken line is
means just enough magnetic field to effect switching magnetization within.

In the ideal case, this switching field corresponds to the corresponding coercivity of the material of the storage film. However, it generally deviates from it by a small factor. However, FIG. 2 shows the ideal case where the switching field is equal to the coercive force Hc. Furthermore, as can be seen from FIG. 2, the curve of the magnetic field strength Hy has a very large gap between the wave high point S1, which has the HSI attributable to the preceding magnetic pole Mpl, and the intersection point P of the switching magnetic field "+HC". This indicates the advantageous fact that a steep course occurs. This means that the magnetic head writes with this very steep slope F between the magnetic poles Mpl and Mp2, which is emphasized by thickening the magnetic field strength curve in Figure 1. . That is, this slope F in the X direction
The so-called magnetic transition length U, which indicates the extent of the magnetic head, is much shorter than in conventional writing with the running edges of known magnetic heads. Furthermore, it can be seen from FIG. 2 that writing by the subsequent magnetic pole Mp2 is practically not possible.

That is, the minimum value that the curved portion of the magnetic field strength Hy to be attributed to this magnetic pole has at its negative peak point S2) (SZ is,
It lies far above the corresponding negative switching field "-Hc", which is indicated by a dashed line. That is, for the storage film 6 of the recording medium of the storage device according to the invention, a material should be selected that has a coercive force Hc that produces a correspondingly high switching field. The materials used for this purpose are generally known (e.g. European Patents No. 0120413 and European Patent Nos.
054269). Further, in FIG. 2, a curve of the magnetic field strength Hx of the (longitudinal) magnetic field component configured in the movement direction (2) is drawn by a chain line.

The curve in Figure 2 shows that the write current ■ is the magnetic pole Mp of the leading magnetic leg.
It is based on a magnetic head 1 that produces a maximum H5I of l and a minimum H52 of the magnetic pole Mp2 of the magnetic legs of l & continuation. In contrast, if the write current flows in the reversed direction, a corresponding, but mirror-image field distribution with respect to the X-axis is obtained.

The magnetization characteristic corresponding to the curve of FIG. 2 is shown in FIG. To simplify the explanation, a recording medium with only an ideal vertical thin storage film 6, a so-called double film, is assumed here. This figure shows a magnetization curve with the magnetization M on the vertical axis and the magnetic field strength H on the horizontal axis in arbitrary units. For such a thin film made of a material with saturation magnetization Ms, the demagnetization rate N in the direction normal to the film is exactly N
-1. That is, in this case, the residual magnetism M1 and the coercive force Hc are equal: Mf=Hc.

Before the start of the writing process, the location to be written is located on the hysteresis curve at point PO. The magnetic head moving relative to the storage film first has its maximum write magnetic field strength I.
The leading pole Mpl with Hs, l>Hc performs a switching magnetization of the storage film, so that the magnetization moves along the hysteresis curve to the point PI. Then the vertical magnetic field is applied to both magnetic poles Mpl
and Mp2, and at that time, point P2 on the vertical axis
, and finally takes a negative value with magnitude 1Hs21<Hc.

Point P3 is then reached on the magnetization curve. A subsequent reduction of the magnetic field to zero terminates the magnetization reversal and thus also the writing process. The corresponding point on the vertical axis is marked P. Point P, coincides with point P2. Since the magnitude of the read signal is proportional to the magnetization of this point P4, the vertical magnetic field of the magnetic pole Mp2 running away must satisfy the inequality %. When formulating this inequality,
When the direction of write current I is reversed, H5I becomes negative and H5I becomes negative.
It is taken into account that 5+2 is positive.

FIG. 3 is for a recording medium A having a single layer film as a storage film. In particular, when using a double-layer storage medium with a soft-magnetic base 7 made of NiFe, CoZr5CoHr, etc., in addition to a storage film made of CoCr, all the critical values shown in FIG. dimensions: g, (d++g/2), (d2+g/2), (f+D
) should be additionally taken into account that is related to the minimum magnetic flux alternating wavelength.
(See pages 611-1613). - The advantage of such a double membrane 6.7 compared to a heavy membrane is that when writing, a much larger vertical magnetic field is strongly favored by the soft-magnetic base 7 at the expense of the undesirable horizontal magnetic field. is obtained. The magnetic film is in this case switched magnetized much more deeply and sharply, so that the readout signal is also advantageously increased significantly.

The magnetic head of another storage device according to the invention, shown partially in longitudinal section in FIG. 4, has a configuration that corresponds essentially to the configuration of the magnetic head l shown in FIG. Accordingly, elements that correspond to each other in the drawings are given the same reference numerals. Both magnetic legs and 10 of the magnetic head denoted by reference numeral 24 are similarly constructed of a magnetic film 9a or lOa having a film thickness d or d2, respectively. In contrast to the embodiment according to FIGS. 1 to 3, in the case of the embodiment according to FIG. It is being carried out regarding. Therefore, in the embodiment according to FIG. 4, materials with different saturation magnetizations Ms should be selected according to the invention for the magnetic film, and in this case, as seen in the relative movement direction V, The material of the magnetic film 9a should have a higher saturation magnetization MS+.

The magnetic film 1 of the subsequent magnetic l111110 is lower than that.
The saturation magnetization of the 0a material is designated M S 2.

The values of the saturation magnetizations Ms1 and Ms2 are in particular at least l.

They should differ by a factor of 4. Materials for the magnetic films 9a and 10a are particularly suitable, for example "permalloy" or alloys such as amorphous CoZr or CoHf alloys. At that time, the larger saturation magnetization M
S + exceeds 1000 kA/m, preferably 11
00 kA/m, while the smaller saturation magnetization M S 2 has a value of less than 900 kA/m, preferably less than 800 kA/m.

"Permalloy", for example, has a saturation magnetization of the order of 800 kA/m, while the saturation magnetization of the two-component amorphous material is of the order of 1100 kA/m. In some cases, 3 with higher saturation magnetization M S I
It is also conceivable to use amorphous alloys of the components. The saturation magnetization Ms of the individual membranes can then be influenced in a known manner by the manufacturing conditions or by the selection of the alloy composition.

Furthermore, as can be seen from FIG. 4, each of the magnetic pedestals and two may be provided with an additional relatively thick magnetic film 9b or 10b outside the area occupied by the end area 11 or 12. These magnetic films in particular cover the central region 15 with the coil winding 18 . The thickness of these additional magnetic films 9b and 10b is indicated by d3 or d4. Advantageously, these additional magnetic films serve to reduce the reluctance in the conductor 8 and are furthermore utilized to make the distribution of the write field asymmetry as desired.

This desired asymmetry is achieved by selecting the thickness of the individual magnetic films or the saturation magnetization of their materials.

That is, the film [d+] of the magnetic film 9a of the preceding magnetic leg having a high saturation magnetization MsI may be the same as the magnetic film 10a of the succeeding magnetic leg 10 having a lower saturation magnetization Ms2, depending on the case.
Membrane J! ! Advantageously, it is selected to be larger than d2. Furthermore, it is not possible to use a material having a saturation magnetization Ms3 larger than the saturation magnetization Ms4 of the material of the additional magnetic film 10b of the subsequent magnetic leg 10 for the additional magnetic film 9b of the preceding magnetic leg 10. It's advantageous. In the illustrated embodiment, the magnetic H'! ! Since it is assumed that the same material is used for 9b and lOb as the magnetic film 9a or loa adjacent to them, respectively, M s 3 =M
sI and M S 4 = M S 2 holds true.

However, it is also possible to select a material with a different saturation magnetization.

It is particularly advantageous to use materials with different magnetic permeabilities in addition to a predetermined saturation magnetization for at least some of the individual magnetic films of the magnetic head H shown in FIG. The basis here is the reversible i3 magnetic flux of the material. That is, in particular, for the magnetic film 9a that defines the gap 13 of the preceding magnetic leg, a material is selected that has a magnetic permeability μrl larger than the magnetic permeability μr2 of the magnetic film 10a that defines the gap 13 of the subsequent magnetic leg 10. It is possible. Due to this measure, the magnetic film 10a can no longer accept an additional magnetic flux at high write currents I, so that a further increase in the write current l is limited by the magnetic film 10a, which is made of a material with a much higher saturation magnetization Msl. This leads to the fact that the magnetic film 9a of the magnetic leg has a writing function. On the other hand, during reading, as is well known, the magnetic field emitted from the storage film 6 of the recording medium A is relatively small.
This magnetic field cannot drive the magnetic film 10a made of a material having a smaller saturation magnetization M s 2 to a saturated state.

As a result, this magnetic film also performs a read function. That is, during reading, the magnetic head 1↓ operates with the well-known good efficiency as a normal ring head.

In order to ensure this characteristic manner of operation of the magnetic head 1±, that is, to avoid overwriting of information written by a preceding magnetic leg 10 by a subsequent magnetic leg 10,
In this magnetic storage device according to the invention, the coercive force Hc of the storage film 6 on the storage medium is also selected so high that the magnetic field of the running away magnetic pole Mp2 is no longer sufficient to write into the storage film 6. The corresponding magnetic field ratios are shown in more detail in FIG. At that time, the absolute value of the coercive force Hc is at least 3
It should be 0 kA/m, preferably at least 60 kA/m.

In FIG. 5, the strength H of the magnetic field generated by the magnetic poles Mpl and Mp2 is shown in relation to the extent X in the direction of movement V of the magnetic head. At this time, the strength of the magnetic field is measured in the normal direction (X direction) on the surface of the recording medium. Furthermore, FIG. 5 shows a leading magnetic pole Mpl and a following magnetic pole Mp.
2 is shown schematically, although not dimensionally correct.

As can be seen from FIG.
It has ln. This scratch clearly corresponds to the memory film 6 (
The switching magnetic field "-Hc" (negative) is below the switching magnetic field "-Hc".Here, this switching magnetic field "-Hc" shown by the broken line is
means just enough magnetic field to effect switching magnetization within.

In the ideal case, this switching field corresponds to the corresponding coercivity of the material of the storage film. However, it generally deviates from this by a small amount. However, FIG. 5 shows the ideal case where the switching field is equal to the coercive force HC.

Furthermore, as can be seen from FIG. 5, the curve of the magnetic field strength H7 exhibits the advantageous fact that a very steep course occurs between the minimum Hmln and the point of intersection S with the switching field "-Hc". ing. This means that the magnetic head has this extremely steep slope F' between the magnetic poles Mpl and Mp2, which is emphasized by thickening the magnetic field strength curve in FIG.
means to write by. That is, the so-called magnetic transition length U indicating the extension of this slope F' in the X direction
is much shorter than the previously known writing by the running edge of the known magnetic head. Furthermore, it can be seen from FIG. 5 that writing by the subsequent magnetic pole Mp2 is practically not possible. The maximum of the curve section of the magnetic field strength H7 to be attributed to the magnetic pole ()1max is much smaller than the corresponding negative switching field "+Hc", which is indicated by the dashed line. That is, for the storage film 6 of the recording medium A of the storage device according to the invention, a material should be selected that has a coercive force HC that produces a correspondingly high switching field. The materials used for this purpose are generally known (e.g. European Patents Nos. 0120413 and 005426 mentioned above).
(See Specification No. 9).

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of one embodiment of the storage device according to the invention, FIG. 2 is a diagram showing the perpendicular magnetic field components generated by the magnetic head of the storage device according to FIG. 1, and FIG. 3 is a diagram showing the corresponding magnetization ratio. FIG. 4 is a schematic diagram of another embodiment of the storage device according to the present invention, and FIG. 5 is a diagram showing the perpendicular magnetic field component generated by the magnetic head of the storage device according to No. 4. ■... Magnetic head, 3... Substrate, 6... Note (Q film' 1... Magnetic conductor, Y... Leading magnetic leg, 9a, 9
b...Magnetic film, soil ■...Subsequent magnetic leg, 10a, 10
b... Magnetic film, 11.12.12', 12''... End range of magnetic leg, 13... Air gap, 15... Center range, 1
6... Connection range, 17... Intermediate space, 18... Coil winding, 22... Etching recess, 24... Magnetic head. tsH8) The agent was Rishi Tomimura.

Claims (1)

[Claims] 1) A thin-film magnetic head constructed in layers on a non-magnetic substrate, and a magnetized head made of a material having a predetermined coercive force, in which information is written along a track by perpendicular magnetization. and a recording medium provided with a possible storage film,
The magnetic head has a ring-head-shaped magnetic conductor that guides magnetic flux, the magnetic conductor has two magnetic legs, and each of the two magnetic legs has at least one magnetic film having predetermined magnetic properties. and the magnetic poles of the two magnetic legs pointing towards the recording medium are arranged one after the other, viewed in the direction of (relative) movement of the head, with a gap of a predetermined width. is configured, and two magnetic legs are located outside the magnetic pole range to define an intermediate space through which writing and/or
In a magnetic storage device in which the winding of a readout coil extends, at least one magnetic film (10a) of a trailing magnetic leg (10a) when viewed in the direction of movement (v) is arranged so that at least one of its magnetic poles (M
p2) within the end ranges (12, 12', 12'') of which the magnetic properties (magnetic resistance R_M_2; saturation magnetization M_s_
Regarding 2), it is different from at least one magnetic film (9a) in the end range (11) constituting at least the magnetic pole (Mp1) of the preceding magnetic leg (¥9¥), and the recording medium ( Coercive force of the material of the memory film (6) in A)
H_c) is selected to be sufficiently high, so that overwriting of the storage medium (A) by the magnetic field to be generated in the magnetic pole (Mp2) of the subsequent magnetic leg (￥10￥) is at least almost eliminated. A magnetic storage device characterized by: 2) The magnetic film (10a) of the subsequent magnetic leg (¥10) is located at least in the end range (12, 1) constituting its magnetic pole (Mp2).
2′, 12″) relatively high magnetic resistance (R_M_2)
, and the magnetic film (9a) of the preceding magnetic leg (¥9) extends at least to the end range (11) constituting the magnetic pole (Mp1).
), the magnetic film (10a) of the subsequent magnetic leg (10) has a magnetic resistance (R_M_1) lower by a predetermined amount than the relatively high magnetic resistance (R_M_2) of the magnetic film (10a). The magnetic storage device according to item 1. 3) Relational expression |H_s_2|≦2・H_c−|H_s_1|where,
H_s_1 and H_s_2 are magnetic heads (¥2¥)
The vertical component of the magnetic field generated on the surface of the memory film (6) is associated with the magnetic pole (Mp1) of the preceding magnetic leg (¥9) or the magnetic pole (Mp2) of the succeeding magnetic leg (¥10). Claim 2, characterized in that a memory film (6) made of a material having a coercive force (H_c) having a predetermined value is provided so that the peak value is satisfied. Magnetic storage device as described. 4) Magnetic film (9a, 10a) of magnetic leg (¥9, ¥10)
) constitutes the magnetic poles (Mp1, Mp2) of the end range (1
1; 12, 12';12''), the magnetoresistances (R_M_1, R_M_2) differ by at least twice in value.
Magnetic storage device as described in . 5) The magnetic film (10a) constituting the magnetic pole (Mp2) of the subsequent magnetic leg (¥10¥) is particularly close to its end range (12, 12')
, 12'') facing away from the storage medium (A) has a cross-sectional reduction (etching recess 22) which increases the magnetic resistance (R_M_2). The magnetic storage device according to any one of Items 6 to 4. 6) The preceding magnetic leg (¥9) has at least its magnetic pole (Mp
Within the range of 1), a predetermined relatively high saturation magnetization (
M_s_1) consisting of at least one magnetic film (9a) of a material with
¥) is at least within the range (12) of its magnetic pole (Mp2) by a predetermined magnitude higher than the relatively high saturation magnetization (M_s_1) of the magnetic film (9a) of the preceding magnetic leg (¥9¥). It has at least one magnetic membrane (10a) consisting of a material with a low saturation magnetization (M_s_2) so that at least a range (12) of subsequent magnetic poles (Mp2) flows through the coil (18) during a write function. Write current (I
2. The magnetic storage device according to claim 1, wherein the magnetic storage device is driven to a magnetic saturation state based on the following. 7) Magnetic leg of magnetic head (￥2￥) (￥9￥, ￥10￥)
at least one of them has a predetermined saturation magnetization (M_s
In addition to the first magnetic films (9a, 10a) made of a material having magnetic poles (Mp1, Mp2)
7. Magnetic storage device according to claim 6, characterized in that it has at least one additional magnetic film (9b, 10b) outside the range (11, 12) of ). 8) The magnetic film (9a) forming the magnetic pole (Mp1) of the preceding magnetic leg (¥9¥) has a saturation magnetization (M_s_) of at least 1000 kA/m, preferably greater than 1100 kA/m.
1) The magnetic storage device according to claim 6 or 7, characterized in that the magnetic storage device is made of a material having the following properties. 9) The magnetic film (10a) forming the magnetic pole (Mp2) of the subsequent magnetic leg (¥10¥) is made of a material having a saturation magnetization (M_s_2) of at least less than 900 kA/m, preferably less than 800 kA/m. A magnetic storage device according to any one of claims 6 to 8, characterized in that: 10) The magnetic film (9a) forming the magnetic pole (Mp1) of the preceding magnetic leg (¥9) is the same as the magnetic pole (Mp1) of the succeeding magnetic leg (¥10).
Saturation magnetization (M_
9. The magnet according to any one of claims 6 to 9, characterized in that it is made of a material having a saturation magnetization (M_s_1) at least 1.4 times greater than the value of s_2). Magnetic storage device. 11) Both magnetic legs (¥9, ¥1) of magnetic head (¥24)
0￥) but different saturation magnetizations (M_s_3 or M_s
_4), in each case one additional magnetic film (9b or 10b) of a material with a saturation magnetization (M_s_
3) is an additional magnetic film (10 yen) of the subsequent magnetic leg (10 yen)
The magnetic storage device according to any one of claims 6 to 10, which is larger than the saturation magnetization (M_s_4) of (b). 12) Magnetic film (9a, 1
0a) constitutes at least its respective magnetic pole (Mp1 or Mp2) (11 or 12, 12',
12″), each measured in the direction of movement (v), 2μ
According to any one of claims 1 to 11, characterized in that the film has a film thickness (d_1 or d_2) smaller than m, in particular smaller than 1 μm, preferably smaller than 0.7 μm. Magnetic storage device as described. 13) The magnetic film (9a) of the preceding magnetic leg (¥9) at least within the end range (11) constituting its magnetic pole (Mp1), measured in the direction of movement (v), 10 yen) constitutes at least its magnetic pole (Mp2) (12
, 12', 12''), the magnetic storage device according to any one of claims 1 to 12, wherein the magnetic storage device has a thickness (d_1) larger than a thickness (d_2) within 14) Magnetic conductor (¥8) of magnetic head (¥2¥, ¥24¥)
At least some of the magnetic films (9a, 9b, 10a, 10b) of ¥) have different reversible magnetic permeabilities (μ_r_1, μ
_r_2) The magnetic storage device according to any one of claims 1 to 13, characterized in that the magnetic storage device is made of a material having _r_2). 15) The material of the magnetic film (9a) of the preceding magnetic leg (￥9￥) forms at least the end range (11
) which is at least larger than the material of the magnetic film (10a) within the corresponding end range (12) of the subsequent magnetic leg (¥10¥).
15. The magnetic storage device according to claim 14, wherein the magnetic storage device has a reversible magnetic permeability (μ_r_1). 16) Different magnetic legs (￥9￥, ￥10￥) (reversible)
The value of magnetic permeability (μ_r_1, μ_r_2) is at least 2
16. Magnetic storage device according to claim 15, characterized in that they differ by a factor of 5, preferably by a factor of 5. 17) Relatively larger (reversible) magnetic permeability (μ_r_1
) is greater than 1000, preferably greater than 3000. 18) Relatively smaller (reversible) magnetic permeability (μ_r_2
) has a value smaller than 1000, the magnetic storage device according to any one of claims 15 to 17. 19) Both magnetic legs (￥9) of magnetic head (￥2￥, ￥24￥)
¥, ¥10¥) each have an additional magnetic film (9b or 10b)
19. The magnetic storage device according to any one of Items 1 to 18. 20) The storage film (6) of the recording medium (A) has at least two
20. The magnet according to claim 1, characterized in that it is made of a material having a coercive force (H_c) of an absolute value of 0 kA/m, preferably at least 60 kA/m. Magnetic storage device. 21) Any one of claims 1 to 20, characterized in that the storage film (6) of the storage medium (A) is disposed on a lower film (7) made of a soft magnetic material. The magnetic storage device according to item 1. 22) Lower film (7) is Ni-Fe alloy or amorphous CoZ
22. The magnetic storage device according to claim 21, wherein the magnetic storage device is made of r or CoHf alloy.