JPS58203614A - Magnetic head - Google Patents

Abstract

PURPOSE:To lessen the deterioration of frequency characteristics even though a coated metallic tape is driven for a long time, by using a dummy block and a core and forming the dummy block with an Fe-Ni alloy containing no Mo. CONSTITUTION:Vacuum dissolution is applied to a mother alloy having a composition of 68.5wt% Fe, 23wt% Ni, 5wt% Cr, 2wt% Cu, 0.5wt% Mn and 1wt% Si. Then a round rod of 40mm.phi is cast. This rod is cast again at 800 deg.C and with 68% forging ratio to obtain a round rod of 13mm.phi. This rod is rolled at 25 deg.C into a square rod of 3X3mm. and undergoes a heat treatment of 1,200 deg.C in air and then is washed with acid. This square rod is then cut into 3X4mm. size and spot- welded in a shielding case. Then the corner parts of the cut square rod are polished to obtain a dummy block 3. A coated gamma-Fe2O3 tape is driven for 500hr at 47.5cm/sec and 25 deg.C and 60% relative humidity. The deterioration of reproduction frequency characteristics of 14kHz/315Hz is measured as 1.5dB after the travelling of tape together with + or -1dB level variation of 14kHz recording/reproducing output.

Description

DETAILED DESCRIPTION OF THE INVENTION ■ Background of the Invention A Technical Field The present invention relates to a magnetic head. More specifically, the present invention relates to a contact type magnetic head comprising a core and a dummy block, and particularly to improvements in the dummy block.

B In a prior art contact type magnetic head, a dummy block is placed along with a recording or reproducing core on the sliding contact surface of a magnetic recording medium such as a tape, and when the medium is in contact with the dummy block, the dummy block is inserted into the track of the medium or Considerations have been taken to ensure sliding contact with unused areas, improve media running performance, prevent uneven wear of the magnetic core and case, and prevent crosstalk between tracks and induced noise. being done.

In this case, in a magnetic head having a core made of ordinary sendust, permalloy ferrite, etc., a dummy flock made of the same material as the core is used.

By the way, recently, amorphous magnetic alloy thin sheets have attracted attention as a core forming material for magnetic heads due to their excellent soft magnetic properties, and magnetic materials with cores made of amorphous magnetic alloy thin sheets have become popular. The head has been put into practical use.

What about a magnetic head with a core made of such an amorphous X-magnetic alloy thin plate? In this case, since the amorphous magnetic alloy cannot be obtained as a block body, the dummy block cannot be formed from the same stamping process as the core as in the conventional method.

On the other hand, if a dummy block is made of conventional magnetic head core materials such as permalloy, high-hardness permalloy, sendust, and ferrite for a core made of an amorphous magnetic alloy thin plate, the magnetic recording medium may be damaged or the frequency characteristics may deteriorate. There are various disadvantages such as deterioration over time and increased output level fluctuations.

To be more specific, when permalloy or high-hardness permalloy is used as a dummy block, the hardness of the amorphous magnetic alloy will outweigh them, the dummy flock will wear unevenly, and the contact between the medium and the head will be poor. With use, the frequency characteristics may deteriorate and output level fluctuations may increase.

In addition, when using sendust, since the amorphous 3f magnetic alloy for magnetic heads is a Co-based alloy,
A local stain is formed between the sendust dummy block and the amorphous magnetic alloy head, causing corrosion of the dummy block especially under high temperature and high humidity, resulting in deterioration of frequency characteristics.
This causes poor running, increases output fluctuations, and even results in poor appearance.

In addition, since Sendust is difficult to forge, roll, and process, it is ground after casting and used as a dummy block.
The presence of the creative area causes damage to the medium, and manufacturing efficiency is low and costs are high.

Furthermore, when ferrite is used, since it has a higher hardness than an amorphous magnetic alloy, uneven wear occurs, resulting in undesirable phenomena such as deterioration of frequency characteristics, poor media running, and increased output level fluctuations.

On the other hand, the present inventors first mentioned about 1 to 40 wt% of Ni, and if necessary, added Fe-Ni containing Iori, Si, etc.
It is proposed that the alloy should be made of Meeflock.

The Fe--Ni based alloy alloy block according to the present proposal is particularly useful when combined with an amorphous core.

Uneven wear is significantly reduced, and deterioration of frequency characteristics and increase in output fluctuation are also significantly reduced. In addition, the dummy block has a high corrosion resistance, and has various characteristics such as less occurrence of poor running of tape, poor appearance, or corrosion during storage.

However, the Fe--Ni alloy dummy block proposed in the future requires further improvement in terms of storage stability under high temperature and high humidity, deterioration of frequency characteristics due to tape running, and the like.

On the other hand, the present inventors have previously proposed that a dummy block be made of the above-mentioned Fe--Ni alloy to which approximately 15 wt% or less of Cr is added.
The alloy dummy block proposed in the future has improved deterioration in frequency characteristics and storage stability under high temperature and high humidity conditions.

However, the corrosion resistance is not necessarily sufficient, and further improvements in storage stability under high temperature and high humidity are desired, and furthermore, the wear of the coated W r -Fe2O3 tape due to running under high temperature and high humidity conditions is There is also a need for improvement.
In addition, the circumference due to uneven wear 'e1. Improvements are also desired in terms of deterioration of numerical characteristics, etc.

In addition, if a coated medium made of magnetic powder as an alloy, so-called metal tape, is run for a long period of time, this dummy block may become discolored or have deposits on it, causing a difference in level between it and the core of the magnetic head. Due to space loss,
This has the disadvantage that the high frequency component in particular of the frequency characteristics deteriorates, impairing the performance of the coated metal tape.

■ Purpose of the Invention The present invention has been made in view of the above-mentioned circumstances, and provides a magnetic head, particularly a magnetic head having a core made of an amorphous magnetic alloy thin plate, which has less uneven wear.
In addition, it has high corrosion resistance and can be stored under unfavorable conditions, r-F
Corrosion or wear caused by e203 tape running has been improved.
The main object of the present invention is to provide a magnetic head equipped with a novel Fe--Ni alloy dummy block whose circumferential mantissa characteristics do not deteriorate even when a coated metal tape is run for a long time.

The present inventors have conducted various studies in order to find a new dummy block material that meets these objectives, especially when used in combination with an amorphous magnetic alloy core, and have arrived at the present invention. It is.

That is, 1 the present invention provides a magnetic head comprising a dummy block and a core, in which the dummy block o7 has a diameter of 29 to 9.
7.5 wt% Fe, 1-4 Qwt% Ni, l
This magnetic head is characterized in that it is made of a Fe--Ni alloy containing ~15 wt% Cr, 0.5-4 wt% Cu, and no MO.

Note that the present inventors have previously proposed a dummy block made of a Fe-Ni alloy containing Cr, Cu, and MO, so the dummy block of the present invention excludes the addition of Mo. It is. The dummy block of the present invention exhibits the same characteristics as the dummy blocks of the previous proposal.

■Specific structure of the invention Hereinafter, a specific configuration of the present invention will be explained in detail.

The dummy block in the magnetic head of the present invention is made of a Fe--Ni alloy having a predetermined composition.

In this case, the content of Fe and Ni contained as essential components of the metatarsal of the Fe-Ni alloy is 29 to 97%, respectively.
．． 5 wt%, more preferably 60 to 35 wt%, and 1 to 4 Qwt%, more preferably 10 to 3 Qwt%.

In addition, the Cr content, which is also an essential component, is 1 to 15 wt.
%, more preferably 2 to 1Qwt%.

Furthermore, the Cu content of the fourth essential component is 0.5 to 4 wt.
%, more preferably 1 to 3 wt%.

The Fe content is less than 29wt%, and the He1 content is 4Q.
If it exceeds wt%, the amount of wear will be greater than that of the amorphous page, and the uneven wear will be large.

Moreover, when the Fe content exceeds 97.5 wt% and the Ni content becomes less than 1 wt%, the standard potential of the dummy block becomes baser than that of permalloy or the like, resulting in a decrease in corrosion resistance.

Furthermore, if the Cr content is less than 1 wt%, the desired effects of the present invention will not be achieved.

On the other hand, it is preferable to bond the dummy block to the shield case by spot welding, but if the Cr content exceeds 15 wt%, an oxide film will be formed on the surface.
Welding strength decreases, blocks fall off during hardening of the resin mold, corner polishing, etc., and workability during head assembly becomes worse.

In addition, if the Cu content is less than Q, 5 wt%, the desired effects of the present invention will not be achieved.

On the other hand, if it exceeds 4 wt%, the amount of deposits that will adhere to the surfaces of the blocks will increase when the coated metal tape runs for a long time, increasing the problems described above. Additionally, cracks tend to occur during hot forging, making subsequent rolling and wire drawing impossible.

The Fe-Ni alloy in the present invention has F within the above range.
e, Ni-1, as long as it has a Cr and Cu content, even if it is made only of Fe, Ni, Cr and MO, it can be made of Fe, Ni, Cr and Cu and one or more other elements. It's okay.

In such a case, the Fe-Ni alloy is Fe, Ni, Cr.
The composition consisting only of Cu is preferably a composition represented by the following formula CD.

Formula (I, l FeaNibCroCu4 Above formula (, I
), a+c-1-d=100wt%,
a is 41 to 97.5 wt%, b is 1 to 40 wt%, C is 1 to 15 wt%, and d is Q, 5 to 4 wt%. In this case, a is 60 to 85 wt%, b is 10 to 30 wt%,
It is preferable that C is 2 to 10 wt% and d is 1 to 3 wt%, since uneven wear is reduced, corrosion resistance is improved, and deterioration of frequency characteristics and output level fluctuations is further reduced.

On the other hand, when the Fe-Ni alloy is composed of Fe, Ni, Cr, Cu, and one or more other elements, the elements that can be contained include Ti, Zr, and Hf1.
V, Nb 1Ta, W.

Iori, transition elements such as C01Zn, Si, A4. Examples include nonmetallic elements such as B and more than 1ia.

The content of one or more of these other elements is 20w
t% or less. If the total amount of other additive elements exceeds 2Qwt%, the effects of the present invention will be reduced.

Such as Fe, Ni and Cr, Cu, and other elements other than MO, such as Fe-
The Ni-based alloy contains Fe in an amount of 29 wt% or more and less than 97.5 wt%, more preferably 60 to 86 wt%, and 1 to 40 wt%.
%, more preferably 10 to 3 Qwt% of Ni, and 1 to 3 Qwt% of Ni.
15 wt%, more preferably 1 to 3 wt% Cu, and 2
0 wt% or less, 1 to 0.1 to 20 wt% of other elements
It includes more than one species.

Among these, a particularly preferable one is the following formula [
It has the composition shown in ID-[IV).

Formula [H''JFeaNibCroCu, Ivne Above formula [
■], a-J-b -1-c + d + 8
= 100wt%, and a is 39wt% or more97.5
Less than wt%, b is 1 wt% to 40 wt%, C is 1 to 1
5 wt%, d is 0.5 to 4 wt%, and e is 2 wt% or less.

In this way, in addition to Fe, Ni, Cr, and Cu, Fe-Ni alloys containing Iori are particularly characterized in that the amount of C is Q,
When it is 1wt% or more, oxidation resistance during hot forging etc. improves, surface finish during hot processing such as forging becomes good, defects during casting are extremely reduced, and wear resistance is improved. Further, the damage to the medium is greatly reduced.

In this case, in the above formula [■], a is 60 to 86wt
%, O is 10-3Qwt%, C is 2-10wt%, d is 1-3wt%, and e is 1.1.1-Iwt%, then r
- Corrosion resistance during tape running is the same as above, uneven wear is further reduced, corrosion resistance is further improved, and deterioration of frequency characteristics and output level fluctuations is further reduced.

Formula [■] FeaNlbCrcCudSif Above formula [bo]
, a + b −) c −1-d −1-f
= ioowt%, and a is 31 wt% or more 97-
Less than 5 wt%, b is 1 to 49 wt%, C is 1 to 15 wt%
% and d are 0.5 to 4 wt%, and f is 19 wt% or less.

In this way, Fe-Ni alloys containing Si in addition to Fe, Ni, Cr, and CuiC have good castability and a reduced cast structure, especially when the Si content is Q, 1 wt% or more. , wear resistance, etc. are further improved.

However, if Si content/front f exceeds 1Qwt%, workability deteriorates and processing such as rolling and wire drawing becomes difficult.
is 19 wt% or less.

In this case, in the above formula [nail], a is 60 to 85 w
t%, b is 10-30wt%, C is 2-1゜wt%, d
When is 1 to 3 wt% and f is 0.1 to 5 wt%, r
- Corrosion resistance due to tape running is improved, uneven wear is further reduced, corrosion resistance is further improved, and deterioration in frequency characteristics and output level fluctuations is further reduced.

Formula CW ]FeaNi6CrcCuc1MneSi (
In the above formula [■], a + b + c + d
+ e + f = 100 wt%, and a is 29 wt%
97.5wt% or more, b is 1 to 4Qwt%, C is 1
~15 wt%, d is Q, 5 to 4 wt%, e is 2 wt% or less, and f is 19 wt% or less.

In this way, the Fe-Ni alloy containing Mn and Si has a seed content and a Si content of 0.1, respectively.
When it is above wt%, both oxidation resistance and castability improve, the surface accuracy and surface defects of the block body become extremely small, and frequency characteristics, output level fluctuations, amount of wear, damage to the medium, etc. are further reduced ( Become.

In this case, in the above formula [IV], a is 60 to 85w
t%, b is 10-3Qwt%, C is 2-10wt%, d
is 1 to 3 wt%, e is 0.1 to Iwt%, f is 0.1 to
At 5wt%, storage stability under high temperature and high humidity and abrasion resistance during R-tape running are significantly improved, uneven wear is further reduced, and the frequency is 151? Deterioration in performance and output level fluctuations, damage to the medium, etc. are extremely reduced.

To obtain a dummy block from such an alloy,
For example, the master alloy is melted in a vacuum or the like, and then cast.
After this, a YT construction process is usually performed. As a result, casting structures or defects are significantly reduced. After that, if necessary, it is rolled, wire-drawn, etc. to adjust the shape, and in some cases, it is pickled, etc. to remove the oxide film, and then it is cut, and if necessary, it is shaped into the desired shape. A dummy block is obtained by welding or gluing it so that it looks like this, and polishing the corners.

On the other hand, the core in the magnetic head of the present invention is usually formed from a thin plate of an amorphous magnetic alloy.

When an amorphous magnetic alloy is used as a core material, it has good properties as a core, and even after extremely long-term use, there is no difference in the amount of wear between the magnetic block and the core, and the sliding contact of the head with the medium is improved. Good results are obtained in terms of less uneven wear on the surface and less variation in frequency characteristics and output level.

When an amorphous magnetic alloy thin plate is used as the core material, its composition may be of various compositions known for use in cores of magnetic heads, but in particular those with a high saturation magnetic flux density Bs and high retention. A composition represented by icv+ below is preferable in that it is suitable for a magnetomagnetic recording medium. ':' Formula [v'3TxX.

2 in the above formula [v], T is Fe'M and C.

Alternatively, it represents a combination of Fe and CO and one or more of the transition metal elements.

In this case, if necessary, other additive elements added in combination with Fe and CO are transition metal elements other than Fe and Co (5c-xZn; Y% cct; L
a-%-Hf; Ac or higher), for example, Ni
, Ti, Zr, Hf, V, Nb, Ta
, Cr, Mo, W, Mn, Ru, Rh, Pd,
Specific examples include one or more of Os, Ir, Pt, etc., and represent a combination of B with one or more other vitrifying elements.

In this case, examples of other vitrifying elements that may be added in combination with B or Si and B include P,
One or more types of C, Ge, Sn, At, etc. can be mentioned.

On the other hand, in the above formula (V), x+y=100 at%, and y is 20 to 27 at%. That is, Fe
The transition metal element content X with g and CO as essential components is 7
It is 3 to 8 Qat%, and the amount y of the glass-forming element containing B or Si and B as essential components is 20 to 27 at%. When y is 20 at%, it becomes difficult to make it amorphous, and when y exceeds 27 at%, the residual magnetic flux density Bs decreases.

Furthermore, the essential components Fe and CO in the transition metal element components
The content of Fe is 1.5 to 5.6 at%, respectively.
and Col 45 to 78.5 at%.

Fe content less than 1.5 at% (Co content 78.5 at%
greater than at%), or +! If it exceeds 5-6 at%,
Magnetostriction becomes large and magnetic permeability decreases. When CO is less than 45 at%, Bs decreases.

In this case, in the above formula [v], T may consist of only Fe and CO within the above content range;
o and one or more of the other additive elements listed above.

When T consists only of Fe and CO, Fe-containing particles are: 1.
5 to 5.5 at%, more preferably 2 to 5.5 at%,
Co content is 67.4 to 78.5 at%, more preferably 67.5 to 78 at%.

When T includes one or more other elements in addition to Fe and Co, one or more of the other transition metal elements can usually be contained up to a total of 25 at %. If the content exceeds this range, problems such as decreased Bs and poor surface properties will occur.

One example of such an element is Ni.

Addition of Ni has the effect of replacing Co and reducing material costs, but as Ni1t increases, Bs decreases, so the Ni content is preferably 8 at% or less.

On the other hand, as one or more other elements, iron group (Fe, C
It is preferable that the total amount of at least one transition metal element other than the iron group is 12 at % or less. At this point, the decrease in Bs is small, and excellent effects unique to each additive element are realized.

In particular, such elements include Ru and/or C.
r is preferred.

In particular, when Ru is added in an amount of 05 to 8 at%, wear resistance is improved, and surface properties, punching workability, etc. are improved.

Further, 1 to 8 at% Cr is added. This improves corrosion resistance.

When 0.5 to 3 at % of U and 1 to 6 at %, especially 2 to 5 at % of Cr are added together, these effects are further improved and more favorable results are obtained.

These Ru, Cr, Ni, etc. IK-me, Ta.

It is also possible to contain one or more of Ti, W, Mo, and the like.

In addition, when transition metal elements other than Fe and Co are possessed in this way, the total of these becomes 20 at% or less, and the Co content is 47.4 to 78.58 t%, more preferably 47.5 t%. ~78 at%, and Fe content is 1.5
The content is preferably 5.6 at% to 5.6 at%, more preferably 2 to 5.5 at%.

On the other hand, the vitrification element component X has B or Sl and B as essential components.

In the case of Kono, when the B content is 3.3 to 27 at% and the S1 content is O to 16.2 at%, Bs increases, the surface properties of the thin plate improve, and favorable results are obtained.

And the B content is 14.1 to 26.9 at%, Si
When the content increases from 0.1 to 5 Jat%, Bs becomes higher, surface properties are further improved, and fLu, Cr
The effect of addition of additional elements such as the like becomes significant, and more favorable results are obtained.

Note that the vitrification element component X may contain one or more elements other than Si and B, if necessary. However, if the total amount exceeds Q, 5 at%, it becomes difficult to become amorphous, so the content is preferably 15 at% or less.

A thin plate having a composition as detailed above is an amorphous material having substantially no long-range regularity.

The thickness of the plate is about 10 to 200 microns.

Such an amorphous magnetic alloy thin plate is manufactured according to a known high-speed quenching method.

Such amorphous magnetic alloy thin plates are usually laminated with an insulating adhesive interposed therebetween to form core halves of a desired shape, and these are butted together to form a core half as shown in FIG. 1, for example. , -core 2.2'. Alternatively, instead of laminating the thin plates, a core half of the desired shape is formed from the thin plates themselves,
The core is formed by combining these core half-days.

In addition to being formed from such an amorphous thin plate, the core 2.2' may also be formed from sendust.

At this time, the hardness or wear resistance of the core and the dummy block described below are similar, uneven wear is reduced, and deterioration of frequency characteristics and output fluctuations is reduced.

The magnetic head 1 of the present invention is shown in FIG. 1 or 2, for example.
As shown in FIG. 3, the core 2.2' and the dummy flock 3 as described above are provided. That is,
...-For example, a core 2.2' and a tammy block 3 are stored in a shield booth 4 of Malloy et al. They are arranged on the sliding surface of the medium in an array. In this case, the structure and construction may be performed using various known structures and methods.

In addition, when the Fe-Ni alloy constituting the dummy block 3 is non-magnetic, a ferromagnetic backing part 6 provided in connection with the ferromagnetic shield case 1 is used as shown in FIGS. 2 and 3. The dummy block 3 may be fixedly stored in the cane by lining the tummy block 3 with a spot contact.
In addition, as shown in FIG. 1, it can also be stored on the non-a annotation holding portion 5 provided in the case 4 by spot g contact or the like.

(2) Specific effects of the invention The magnetic head of the invention can be used in various applications such as audio, video, measurement, and digital applications.

In this case, the dummy block of the magnetic head of the present invention is formed from a Fe-Ni alloy containing predetermined Cr and Cu, and the wear resistance of the dummy block is good, and uneven wear of the dummy block is prevented. Based on this, there is much less deterioration in frequency characteristics, etc.

In addition, the corrosion resistance of the dummy block is extremely high, and the corrosion resistance of the dummy block is extremely high. There is no occurrence of poor running, poor appearance, or deterioration of frequency characteristics.:1 These effects are superior to those of Fe-Ni alloys that do not contain either Cr or Cu. indicates a value.

Furthermore, damage to the medium caused by dummy blocks is extremely small.

In addition, the occurrence of crosstalk, induced noise, etc. can be effectively prevented.

Further, if the core is made of an amorphous magnetic alloy thin plate, the characteristics of the core will be good, and uneven wear between the core and the dummy block will be further reduced.

V. Specific Examples of the Invention Next, the present invention will be described in further detail with reference to more specific examples of the invention.

Example 1 Fe58,5wt%, Ni23wt%, Cr5wt%,
A master alloy with a composition of Cu2wt%, MnO, 5wt%, and 511wt% was vacuum melted and cast into a 40+mφ round bar, which was then cast at 800°C with a forging ratio of 68% to form a 13m
A round bar of φ was obtained. Thereafter, this was rolled into a 3 x 3 square bar at 25°C, and then heat treated in air at 1200°C.
The block was pickled, cut into 3×4 pieces, placed in a spot bath in a shield case, and the corners were polished to obtain a dummy block 3 as shown in FIGS. 2 and 3.

Atomic composition of the amorphous magnetic alloy thin plate forming the core 2.2': (Fe, Co, 5), 2RulCr.

(5ltoB9Q)93 was used to fabricate an uninvented magnetic head as shown in FIGS. 2 and 3.

Coating type 1- Using Fe2O3 tape, heat it at 25℃.
50 at 47.5 cm7 sec at 60% relative humidity
After running for 0 hours, the deterioration (dB) of the reproduction frequency characteristics of 14 kHz to 7315 Hz and the variation (dB) of the 14 kHz recording/reproducing output level after running were determined as i++.

Table 1 Present invention 1.5 ±11fZ
-25±9 For comparison, Table 1 also shows the results when the dummy block 3 was formed from permalloy. Also,
The composition of the amorphous magnetic alloy thin plate forming the core 2.2' is
In the above, those containing no Ru and Cr, those excluding Ru or Cr, and those containing Ru and Cr
When a similar experiment was conducted using Ti and Ta in addition to r, almost the same results were obtained.

Example 2 Dummy flocs having the composition shown in Table 2 below were produced in the same manner as in the example.

A magnetic head was created from a total of 15 dummy blocks in the same manner as in Example 1, and a magnetic head of 14 Kf (z/315 H
z) When the deterioration of reproduction frequency characteristics (F characteristics) was measured, the results shown in Table 2 below were obtained.

Furthermore, a total of 1
For each of the 5 magnetic heads, 1-)'e203
tape, 25 at a running speed of 47.5 cm/sec
The amount of wear after 500 hours at 60% relative humidity was measured using a surface roughness meter.

Further, after being stored for 500 hours at 40° C. and 70% relative humidity, the corrosion layer on the surface of each dummy plotter was removed, and the amount of corrosion was measured using a surface roughness meter to evaluate corrosion resistance.

In addition, 1-Fe2O3 tag, 4.7'5 on
/' sec, 40°C, 70% relative humidity, 50
The corrosion resistance was evaluated by running for 0 hours and measuring the amount of wear after running.

Furthermore, we have developed a coated metal tape using alloy magnetic powder.
Run for 2000 Bii at 75 cttt/Sec at 25° C. and 60% relative humidity, 14. KHz/
Deterioration of frequency characteristics at 315 Hz was measured.

In addition, each magnetic head's 125Hz, 160 nwb/m
Recording/playback Recording/playback Crosstalk between 2 troughs Hz, 30e
The induced noise in a parallel magnetic field was measured.

These results are also listed in Table 2 below.

From the above results, a magnetic head equipped with a dummy block made of an uninvented Fe-Ni alloy has extremely low frequency characteristic deterioration and output level fluctuation, low wear, and high corrosion resistance due to storage and running. It can be seen that practically satisfactory values for crosstalk and induced noise can also be obtained.

[Brief explanation of the drawing]

FIG. 1 is a partially cutaway perspective view showing an embodiment of the present invention. FIG. 2 is a partially omitted perspective view showing another embodiment of the present invention, and FIG. 3 is a partial end view of FIG. 2. 1・−・−・−・・−・−Magnetic head 2.2′・−・−Core 3・−・−・・−−−−−・−・−Dummy blocked agent Patent attorney Yo Ishii −

Claims (1)

[Claims] (1) A magnetic head comprising a dummy block and a core, wherein the dummy block has a content of 29 to 97.5 wt%.
A magnetic head comprising a Fe-Ni alloy containing Fe, 1 to 40 wt% Ni, 1 to 15 wt% Cr, and 0.5 to 4 wt% Cu, and containing no MO. . 2. The magnetic head according to claim 1, wherein the Fe-Ni alloy has a composition represented by the following formula [11]. Formula [■] FeaNIbCroCud (In the above formula [■], a-i-b+c+d=l O
0 wt%, a is 41 to 97.5 wt%, b
is 1 to 4Qwt%, C is 1 to 15wt%, and d is 0
．． It is 5 to 4 wt%. ) 3. Fe-1\1 series composite is 29wt% or more 97.5w
less than t% Fe, 1 to 40 wt% Ni, and 1 to 15
wt% Cr, Q, 5-4 wt% Cu, 20
The magnetic head according to claim 1, comprising one or more of the following elements: 4. The magnetic head according to claim 3, wherein the Fe-Ni alloy has a composition represented by the following formula ['']: Formula [■] FeaNlbCroCudMne (formula [■]
], and a + b + c + d + e =
100wt%, a is 3gwt% or more 97.5wt
%, b is 1-4Qwt%, C is 1-15wt%, d
is 0.5 to 4 wt% and 6612 wt% or less. )5
, p6-Ni alloy having a composition represented by the following formula [flr]. Formula [llj) r”eaNibcrccu4s+ f
(In the above formula [Ml]iC, a + b + c
+ d + f = 100 wt%, and a is 31 w
t% or more and less than 97.5wt%, b 1 to 4wt%, C
Ha 1-15 wt%. d is 05 to 4 wt%, and f is 10 wt% or less. )6
, The magnetic head according to claim 3, wherein the Fe-Ni alloy has a composition represented by the following formula (IV). Formula CIV ] FeaNibCroCudMneSi (
(In the above formula [■], ': S, a + c + d + f = 100 wt%, a is 29 wt% or more and less than 97.5 wt%, b is 1 to 4 Qwt%, and C is 1 ~1
5 wt%, d is 0.5 to 4 wt%, e is 2 wt% or less, and f kZIQwt% or less. 7. The magnetic head according to any one of claims 1 to 6, wherein the core is made of an amorphous magnetic alloy or a thick plate. 8. Claim I! where the amorphous magnetic alloy thin plate has a composition represented by the following formula [vl]. A magnetic head according to item 7. Formula [v]TxX. (In the above description [v], 'r is Fe and Co,
or represents a combination of F'e and CO with one or more other 4-transfer metal elements, and X is B, or Sig and B
, f represents B or a combination of Si and B with one or more other glass-forming elements. x+y=100 at
%, and y is 20 to 27 at%. moreover,
The amount of Fe is 1-5 to 5.6 at%, and the amount of Co is 45 to 78.
It is 5 at%. )