JPS6116009A - Magneto-resistance effect type magnetic head device - Google Patents

Abstract

PURPOSE:To decrease the number of independent lines, i.e., terminals by connecting in series conductors for generating bias magnetic fields of plural channels and forming the conductor lines for generation of bias magnetic fields in the number corresponding to the number of tracks. CONSTITUTION:Four MR magnetic head parts h1L, h1R, h2L and h2R are provided in response to tracks L and R of channels ch1 and ch2 respectively of an analog stereo circuit. Then the MR magnetic-sensitive parts 5 and bias magnetic field generating conductors 3 are added. The bias conductors 3 are connected in series between tracks corresponding to each other, i.e., tracks L and tracks R respectively of both channels ch1 and ch2. Therefore the number of independent lines, i.e., terminals of the conductors 3 can be reduced down to just two tracks (terminals TbL and TbR) of a channel. Then terminals TM1L, TM1R, TM2L and TM2R are led out to the part 5 together with a common terminal Tc for each end part of the part 5 and the conductors 3.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention provides a magnetoresistive effect (hereinafter abbreviated as MR) type magnetic head device, particularly an MR type magnetic head element thereof, which provides negative feedback in response to a signal output from the magnetic head device. The present invention relates to an MR type magnetic head equipped with a conductor for generating a bias magnetic field that provides a magnetic field.

? BACKGROUND TECHNOLOGY AND PROBLEMS First, an example of the structure of a head portion of a conventional MR type magnetic head device will be described with reference to FIG.

For example, on a magnetic substrate (11) made of old-Zn ferrite, Mn-Zn ferrite, etc. (this group < H (if 11 has conductivity, 5i0
(via an insulating layer (2) such as
A bias magnetic field generating conductor (3) made of a strip-shaped conductive film that serves as a current 3ffi path for bias magnetic field generation to give a bias magnetic field to 5) is deposited, and on this bias conductor (3), For example, through it 1 (41)
An MR magnetically sensitive portion (5) made of an MR magnetic thin film such as old-Fe alloy or N1-Go alloy is arranged. Then, on this MR magnetic sensing part (5), a thin insulating layer (6) is placed between the
One end of each straddles the bias conductor (3) and the MR magnetic sensing part (5)
A pair of magnetic layers (7) and (81) made of, for example, Mo permalloy are deposited on the substrate (1) as magnetic cores extending transversely to each constitute a part of the magnetic circuit. , through the non-magnetic insulating protection N(9), the protection substrate O
l is joined.

A nonmagnetic gap spacer layer (11) made of, for example, an insulating layer (6) and having a required thickness is interposed between one magnetic layer (7) and the front end of the substrate (1, 1). A front magnetic gap g is formed. Then, a substrate (11, a gap spacer layer (11), a gap spacer layer (
11), the front surfaces of the magnetic layer (7), the protective layer (9), and the protective substrate Ql are polished to form a surface facing the magnetic recording medium (1).
2) is formed.

In addition, the rear end of the magnetic layer (7) and the front end of the other magnetic layer J'! However, a discontinuous portion (13) is formed between both ends, which is spaced apart from each other.The rear end and front end of the celadon magnetic layers (7) and +8), respectively, are covered with an insulating layer (6). Although it is electrically insulated by the intervention of
are made to combine. In this way, the substrate (1
) - magnetic gap g - magnetism 7! (71-MR magnetic sensing part (5
) - Magnetic layer (8) A magnetic circuit consisting of a closed magnetic circuit of one substrate ill is formed.

Such an MR type magnetic head odor ζ is caused by the signal magnetic flux from the front gap g that is in contact with the magnetic recording medium flowing through the above-mentioned magnetic circuit, and the MR magnetic sensing part (5) in this magnetic circuit. The resistance value changes depending on the external magnetic field caused by this signal magnetic flux.

Therefore, if a detection current is passed through the MR magnetic sensing part (5) and this resistance change is detected as a voltage change across the MR magnetic sensing part (5), it is possible to reproduce the recorded signal on the magnetic medium. can.

In this case, in order for the MR magnetic sensing section (5) to operate linearly as a magnetic sensor and to have high sensitivity, it is necessary to magnetically bias the MR magnetic sensing section (5).

This bias magnetic field is a DC magnetic field given by a magnetic field generated by energizing the bias conductor (3) and a magnetic field itself generated by the detection current flowing to the MR magnetic sensing section (5).

That is, this type of MR type magnetic head device, as shown in its schematic configuration in FIG. The signal magnetic field H5 from the magnetic medium described above is applied while the bias magnetic field He is applied by the magnetic field generated by the energization of the detection current I to the MR magnetic sensing part (5). Based on the resistance change caused by this signal magnetic field H9, the voltage across the MR magnetic sensing section (5), that is, the change in the potential at point A, is amplified by the amplification 1 (14) via the low-frequency blocking capacitor (16). The signal is supplied, amplified, and output from the output terminal (15).

FIG. 3 shows an operating characteristic curve diagram showing the relationship between the magnetic field H applied to the MR magnetic sensing part (5) and its resistance value R. This curve shows the range -HBR~ where the absolute value of the magnetic field H is small +HB
R shows an upwardly convex quadratic curve, but when the absolute value of the magnetic field H becomes large and deviates from this range, the MR magnetic sensing part (5
) begins to saturate in the direction of the magnetic circuit, and its resistance R asymptotically approaches the minimum value Rmin away from the quadratic curve. Incidentally, the maximum value Rmax of this resistance R is a value in a state where all the magnetization of the MR magnetic thin film is oriented in the current direction. Then, in the characteristic part of the quadratic curve in this operating characteristic curve, when the bias magnetic field HB mentioned above is applied, the reference numeral (17) in FIG.
) is applied from the magnetic medium, and in response to this, an output based on a change in resistance value, indicated by reference numeral (18) in the figure, is obtained. In this case, it can be seen that as the magnitude of the signal magnetic field increases, the second harmonic distortion increases.

In addition, the potential at point A in FIG. 2 in the above-mentioned MR magnetic head device is determined by the combination of the fixed resistance and the variable resistance of the MR magnetic sensing part (5). The resistance is as high as about 98%, and since the temperature dependence of the fixed resistance is large, there is a drawback that the temperature drift of the potential at point A is large. This MR magnetic sensing part (
5) The resistance value R is R=Ro (1+αcos2θ)
...(1) (However, Ro is the fixed resistance, α is the maximum resistance change rate, and θ is the MR magnetic sensing part (the angle between the current direction and the magnetization direction at 5th angle), For example, when the MR magnetic sensing part (5) is made of an MR magnetic film of 81Ni-19Fe (permalloy) alloy with a height of 250, the actual value of α is approximately 0.017.The value of α is Although there are some differences depending on the thickness and material of the MR magnetic thin film of the MR magnetic sensing part (5), it is at most about α-0.05.

On the other hand, the fixed portion Ro of this resistance is Ro = Ri (1+aΔt) ---・(
2) (However, Ri is the initial value of resistance, a is the temperature coefficient, Δ
t is the temperature change), and the actual measured value of the temperature coefficient a in the example of the above-mentioned MR magnetic sensing part (5) is a = 0
．． It is about 0027/deg. This results in large noise in detecting a DC magnetic field.

Furthermore, in the case of this type of MR type magnetic head unit, since its temperature coefficient is large as mentioned above, the temperature coefficient is generated by, for example, energization to the MR magnetic sensing part (5) or bias current to the bias conductor (3). If this heat is radiated unstably due to the head's sliding contact with the magnetic recording medium and the temperature of the head changes, large noise, so-called sliding noise, will be generated.

Furthermore, when the amplifier (14) in the configuration shown in FIG. The capacitance Mc required for (16) is (ωo=2πfo), where R is the resistance of the MR magnetic sensing part (5). Now, if the MR magnetic sensing part (5) is made of the above-mentioned permalloy with a thickness of 250 and its length is 50 μm, its resistance R will be about 1000, so f o = 1 kl (assuming z, A capacitor (16) with a large value of C=1.3μF is required, especially for multi-track digital/Iz
This poses a problem when constructing a magnetic head device for audio signals.

Also, in the magnetic circuit 4. It is desired that the magnetic permeability of the magnetic layer, especially the magnetic permeability of the magnetic layers (7) and (8) which are relatively thin and have a small cross-sectional area, be as high as possible, and this magnetic permeability is maximum when the external magnetic field is zero. Therefore, applying a bias magnetic field as described above causes a decrease in magnetic permeability.

The DC bias type MR type magnetic head device mentioned above has the advantage of having a wide effective track width and being easily formed into a sandwich track, but on the other hand, it has poor linearity and has difficulty in DC reproduction! With a spatula,
The sliding noise is large and the Barkhausen noise is thick (,
The disadvantage is that the output varies widely.

Other OMR type magnetic head devices include differential type MR
MR type magnetic head devices, Barra ball type MR type magnetic head devices, etc. have been proposed. A differential MR type magnetic head device has a pair of MR magnetic sensing parts in its MR type magnetic head, and a common bias conductor applies the same bias magnetic field to the pair of MR magnetic sensing parts. Differential outputs are obtained from the magnetosensitive sections using the same signal magnetic field, and the differential outputs are supplied to a differential amplifier, and a reproduced signal is obtained from the differential amplifier.

This differential MR type magnetic head device is capable of direct current reproduction (
However, although it has the advantages of low Barkhausen noise, low output fluctuation, and only an amplifier is required as a circuit, it has a small sliding noise reduction effect, a narrow effective track width, and The disadvantage is that it is difficult to make tracks.

In addition, the barber pole type MR magnetic head device has its MR
A large number of mutually parallel conductor bars made of gold or the like are formed on the MR magnetic sensing part of the magnetic head so as to be oblique to the longitudinal direction of the magnetic head.

This barber-pole type MR magnetic head device has the advantage of having low Barkhausen noise, little variation in output, and requires only an amplifier as a circuit. However, it is difficult to reproduce DC current, has large IR dynamic noise, and has narrow tracks. It has the disadvantage that the effective track width is not very wide.

Therefore, in order to eliminate or improve the above-mentioned drawbacks,
Previously, the present applicant filed an application for a new magnetoresistive magnetic head device in Japanese Patent Application No. 1983-38980. An example of this MR type magnetic head device will be explained with reference to FIG.

In this example, the MR type magnetic head section adopts the same configuration as that explained in FIGS. 1 and 2, and the fourth
In the figure, parts corresponding to those in FIGS. 1 and 2 are denoted by the same reference numerals, and redundant explanation will be omitted. In this example, MR
A high-frequency rc low-level AC bias current iA is superimposed on the DC bias current iB through the bias conductor (3) of the type magnetic head section, and the high-frequency magnetic field is superimposed on the DC magnetic field and applied to the MR magnetic sensing section ( 5). Here, the waveform of the AC bias current iA, and thus the waveform of the AC magnetic field, may be a sine wave, a rectangular wave, or any other waveform.

In this way, since the AC bias magnetic field is applied to the MR magnetic sensing part (5) superimposed on the DC bias magnetic field, the frequency fc is applied between both ends of the MR magnetic sensing part (5), that is, at point A in FIG. An alternating current signal is extracted.

Figure 5A shows the DC bias magnetic field HB and the magnetic fields H and M when the AC bias magnetic field HA is superimposed on the signal magnetic field Hs.
The relationship with the resistance R of the R magnetic sensing part (5) is shown. Here, when the amount of change ΔH in the AC bias magnetic field HA is small, the magnitude of the resistance change ΔR with respect to the change in the AC bias magnetic field at the instant of change is obtained as the absolute value of the differential of the quadratic curve in FIG. As shown in Figure 5B, the DC bias magnetic field H
In principle, the relationship between B, the magnitude of the signal magnetic field H3, and the resistance change that is the output is a straight line. Therefore, the magnitude of the AC signal obtained at point A in FIG. 4 is an output that changes depending on the change in the sum of the DC bias magnetic field HB and the signal magnetic field H5 from the magnetic recording medium.

As shown in Fig. 4, this output is passed through a high-pass filter (preamplifier) (
19) to a rectifier (20) for rectification, and the rectified output is supplied to a low-pass filter (21). In this way, the signal magnetic field H5 from the magnetic medium
A signal output can be obtained according to the In this case, the alternating current i
The frequency fc of A is now, for example, finally at the output terminal (15)
If the band of output obtained from 0 to 100 kHz is required, a frequency sufficiently higher than this, for example f c = I M
)+2. In this case, a high-pass filter (
19), the low cutoff frequency is selected to be higher than 100 kHz and lower than the frequency fc, for example 'I=11 MHz, for example 500 kHz. However,
The output of the high-pass filter is converted into a rectifier (20
), the cutoff frequency is 100kt.
(By passing through the low pass filter (21) of z, a signal in the band of 0 to 100kHz is obtained at the output terminal (15).

In a magnetic head device having such a configuration, the sixth
The external magnetic field shown in Figure A (signal magnetic field bias conductor
In the case of a saw applied to the magnetic sensing part (5), point B in Fig. 4
As shown in Fig. 6B, an output is obtained by amplitude modulating the carrier of frequency fc with a signal, and as shown in Fig. 6C, an output corresponding to the signal magnetic field is obtained at the output terminal (15). Served.

According to such a magnetic head device, an output with a linear operating characteristic corresponding to the differentiation of the operating characteristic by the magnetic field vs. resistance quadratic characteristic curve of the MR sensing section (5) is extracted, so that a reproduced signal without distortion can be obtained. It is something that can be released.

Furthermore, even if the fixed portion of the resistance of the MR magnetic sensing section (5) has a large temperature dependence, the fixed portion of this resistance depends on the characteristics obtained by differentiating the operating characteristic curve of the MR magnetic sensing section (5) The influence of temperature drift can be significantly reduced.

Furthermore, as mentioned above, by eliminating the influence of the temperature dependence of the resistance-fixing bone of the MR magnetic sensing part (5), the generation of noise caused by the sliding of the MR type magnetic head part with the magnetic medium mentioned above is reduced. be able to.

Also, a capacitor (16) in such a magnetic head device
Since it is sufficient to pass the component of frequency fc, for example, if f c -500kHz, this capacitor (1
The capacitance @C of 6) should be C=2600pF. If this frequency fc is further increased, this capacitance C
can be made even smaller.

FIG. 7 shows another example of the previously proposed MR type magnetic head device. In FIG. 7, parts corresponding to those in FIG. 4 are given the same reference numerals, and redundant explanation will be omitted.

In this case, only an alternating current bias current i71 is made to flow through the bias conductor (3) without a direct current bias current flowing through it. FIG. 8 schematically shows this operation. In this figure, the solid line curve is the operating characteristic curve of the magnetic field versus resistance of the actual MR magnetic sensing part, but if you extrapolate the quadratic curve part of this characteristic, the dashed line will look like water, and this will result in the minimum resistance. The magnetic field corresponding to the value Rmin is +Ho and -Ho
shall be. In this example, an alternating current bias magnetic field HA is applied superimposed on the signal magnetic field Hs, and a resistance change of the MR magnetic sensing part (5) corresponding to the polarity and magnitude of the signal magnetic field and in response to the alternating current bias magnetic field is obtained.

The operating characteristic curve in this case is a quadratic curve, and the resistance value R of this MR sensing section (5) is expressed as follows.

Here, ΔRmax is ΔRmax = Rmax − Rm
It is given in. The magnetic field 1 given to the MR magnetic sensing part (5) is expressed by the bias magnetic field HA (tl and
It is expressed as the sum of the signal magnetic field Hs (tl).

H(t)=HA ft)+H5(t)
・−・−+51 Here, the magnetic field HA (tl is obtained by the current flowing through the bias conductor (3), and HA (t) = H8o □ sin (
ωct ) ... f5). However, the angular frequency ωC is expressed as in the following equation.

ωG=2 π fc...(
7) MR magnetic sensing firIifi) output voltage V (t)
When the MR detection current is I, V (t) 1 - R (8) is expressed as follows from the above equations (4), (5), and (6).

X5in ωc + (Hs (tll 2)...
(9) Next, this output voltage V [11 and AC bias magnetic field H
A signal having the same phase and frequency as A, for example, sin (ωct) is multiplied by a multiplier (22). Its output Vz(tl
is expressed as the following equation.

Vz(t>VTtl・sin (ωc t)+28Ao
−Hs(tl・sin (ωc t) + (Hs (
t)) 2) ・sin (ωc t)...Q(I
t and then passes it through a low-pass filter (21), resulting in
When the order Q[I+ has a ωC component 1- Rmax
−sin (ωct) = 0” (
11) HA♂・5jn2(ω(Ht) ...(12) 2 HAO-Hs (tl ・ sin'(ω
t )-HAo-Hs(tl (1-cos(2
ωt)1- HAO・H3(
... (13) (Hsft
ll 2・5in(ωt) −〇”...(14
). Therefore, the output voltage V o (tl) which is jη at the terminal (15) is as follows, and a voltage proportional to the signal magnetic field Hs(t) is obtained. In this case, the multiplier (22) Even if the signal magnetic field component Hs (tl) is included in the input to the signal, the high-pass filter (19) can be omitted because there is little amount of it mixed into the output.

According to such an MR type magnetic helix device, an output corresponding to the polarity of the external magnetic field can be obtained, and in addition to the same advantages as the previous example, there is an advantage that the dynamic range is widened. Further, in this case, there is an advantage that by using only the AC component as the magnetic bias, it is possible to avoid a decrease in the magnetic permeability of the magnetic circuit due to the DC bias.

According to an MR type magnetic head device that applies such an AC bias, it is possible to obtain an output with excellent linearity and low distortion, enable DC reproduction, have small temperature drift, and improve sliding noise. It has the advantage that the effective track width is large, the track can be narrowed, and the capacitance of the capacitor can be made small. Furthermore, when using the configuration explained in FIG. 7, it is possible to obtain a large dynamic range. If it is possible to do so, it is also possible to avoid a decrease in the magnetic permeability of the magnetic circuit.

Furthermore, the present applicant has proposed that in an MR type magnetic head device in which an alternating current bias magnetic field is applied to such an MR magnetic sensing part, linearity is further improved and distortion is further reduced.
On June 8, 1982, we introduced an MR type magnetic head device that reduces Barkhausen noise, has a wider dynamic range, and reduces output variation.
The date was proposed in the patent application [Magnetoresistive magnetic head device]. This MR type magnetic head device includes an MR magnetic sensing section to which a signal magnetic field is applied, an AC magnetic field generation means for applying an AC bias magnetic field to the MR magnetic sensing section, and a signal output from the output of the MR magnetic sensing section according to the signal magnetic field. The present invention is characterized in that it has a signal extraction means for extracting the signal, and a negative feedback magnetic field generation means for applying a negative feedback magnetic field to the MR magnetic sensing section according to the signal output from the signal extraction means.

According to this, in an MR type magnetic head device in which an alternating current bias magnetic field is applied to the MR magnetic sensing part, linearity is further improved, distortion is further reduced, Barkhausen noise is reduced, and dynamic It is possible to obtain a wider range and less variation in output.

Further, referring to FIG. 9, a specific example of the configuration of this MR type magnetic head will be explained. This example is applied to the magnetoresistive magnetic head shown in FIG. 7, and parts in FIG. 9 corresponding to those in FIG. 7 are given the same reference numerals and redundant explanation will be omitted. That is, the signal output from the low-pass filter (21) is supplied to the buffer amplifier (23), and the current ir from this is supplied to the buffer amplifier (23).
B flows through the bias conductor (3), and this bias conductor (
3) (provide a separate bias conductor to which the current ips
A negative feedback magnetic field HFB is generated from the negative feedback magnetic field HFB and applied to the MR magnetic sensing part (5).

FIG. 10 shows an equivalent circuit of the MR type magnetic head device of FIG. 9, where Hs (t)=
Mfxl ・φrn (j2π/λ)・・・(16
) is generated, and at the same time, a feedback magnetic field -Hps (tl) is generated.

In this way, the output voltage V (tl) from the MR magnetic sensing part (5) is V (tl-φh ・(Hs (tl-Hps(
tl) −(17) is obtained. Also, signal extraction means (circuit (16)).

(consisting of (19), (22), (21))
As output signal Vo(tl), Vo(tl=A (jω) ・V(t)
...(18) is obtained. Also, the return magnetic field −Hp
e (tl is −HFB(tl= K −A (jω)
... is expressed as (19).

In addition, φm (32π/λ) is a transfer function on the input side of the MR magnetically sensitive section (5) (where λ is the wavelength), φh is a transfer function on the output side of the MR magnetically sensitive section (5), and A( jω) is the transfer function of the signal extraction means, K is the transfer function of the buffer amplifier (23), and φ is the transfer function of the bias conductor (3).

FIG. 11A shows a characteristic curve of the magnetic field versus resistance of the MR magnetic sensing part (5). and signal magnetic field H
When a superimposed magnetic field of s(tl is applied, the MR magnetosensitive section (5) obtains an output voltage () as shown in FIG. 11C. In the multiplier (22), this output voltage V By multiplying 11 by the rectangular wave alternating current shown in Figure 11, the output side of the low-pass filter (21) has a signal output V o (corresponding to the signal magnetic field Hs (tl) in Figure 11B).
tl is output.

Next, when a single frequency signal of 315 FIz is recorded on a magnetic tape and played back with various magnetic head devices,
FIG. 12 shows the characteristics of second and third harmonic distortion of the signal output with respect to the recording level. In this case, a metal tape was used as the magnetic medium. Tape speed is 4.7cm/s
It was ec. The recording magnetic head was a normal ring-shaped magnetic head. In the case of an MR type magnetic head device, its M
The detection current iMR flowing through the R magnetic sensing part (5) is 5 mA, the rectangular wave alternating current 18 flowing through the bias conductor (3) is 5 mA,
Its frequency was 250kHz.

Curve B2. B3 shows the characteristic curves of second-order and third-order harmonic distortion of the output signal from the MR magnetic head device shown in FIG. 7, and curves A2. It can be seen that the distortions are considerably large compared to the characteristic curves of second and third harmonic distortion of the output signal from a normal ring-shaped magnetic head device shown in A3.

On the other hand, curves C2 and C3 show the characteristic curves of second- and third-order harmonic distortion of the output signal from the MR magnetic head device shown in FIG. 9, respectively, and curve A2. It can be seen that the distortion is similarly small compared to the characteristic curve of second- and third-order harmonic distortion of the output signal of an ordinary ring-shaped magnetic head device shown in A3.

Next, another example will be explained with reference to FIG.

This example is applicable to the magnetoresistive magnetic head device shown in FIG. 4. In FIG. 13, parts corresponding to those in FIG. 4 are given the same reference numerals, and redundant explanation will be omitted. That is, the signal output from the low-pass filter (21) is supplied to the hasher amplifier (23), the current ire from this is passed through the bias conductor (3), and the bias conductor (3) (separate bias conductor A negative feedback magnetic field HFB is generated from the negative feedback magnetic field HFB and applied to the MR magnetic sensing part (5). For other explanations, the explanation of the example shown in FIG. 9 will be referred to.

Note that the reproduction signal is not limited to a digital audio signal, but may also be a digital video signal, an analog audio/video signal, etc.

The MR sensor is configured to apply an alternating current bias magnetic field to the MR sensing section as described above, and also to apply a negative feedback magnetic field according to the output.
The R-type magnetic head device has the advantages of improved linearity by -M, less distortion, less Barkhausen noise, wider dynamic range, and less variation in output.

However, when such an MR type magnetic head has a multi-element magnetic head configuration that requires a plurality of MR magnetic heel F sections each having an MR magnetic sensing section, it is necessary to apply a negative feedback magnetic field independently to each magnetic head. Therefore, it is necessary to provide independent bias lines for each. now,
For example, if we consider a reproducing magnetic head having a track configuration in which there are two channels chx and ch2 of analog stereo lines consisting of left and right signal tracks L and R, respectively, in this case, as shown in FIG.
Four MR magnetic head sections hIR, h2L, and h2R are provided corresponding to the two tracks L and R, respectively.

In this case, each MR1d! 1ki head part hlL, hI
Regarding R+h2L, h2R, terminals Tb5t, , TbtR, Tb2L, T are connected from each MR magnetic sensing part (5), respectively.
While deriving b2n, each bias conductor (3
), and from these terminals T old LIT old R, 7M2
It is necessary to derive L, Tll2R. Tc is total M
A common terminal, for example, a ground terminal, is shown, to which one end of each MR magnetic sensing part (5) and bias conductor (3) of the R magnetic head section is commonly connected.

That is, in the case of the above configuration, if the number of channels is N (N-2 in the example of FIG. 14) and the number of tracks of each channel is m (m-2 in the example of FIG. 14), the number of terminals is 2mN+1 (20)

OBJECTS OF THE INVENTION The present invention aims to reduce the number of independent lines, that is, the number of terminals, in the above-mentioned MR type magnetic head.

Summary of the Invention In the present invention, a magnetoresistive magnetic head section corresponding to m tracks operating simultaneously is provided for N channels, and one channel of these N channels is selectively operated. In a magnetoresistive magnetic head device used in a magnetoresistive magnetic head device, bias magnetic field generating conductors of magnetic head elements for respective tracks of N channels are connected in series, and m independent bias magnetic fields are generated. Form a conductor line for generation.

That is, in the present invention, for example, even in the case where a conductor for generating a bias magnetic field is provided to apply a negative feedback magnetic field corresponding to the output to the MR magnetic sensing section of each magnetic head section described above, for example, as shown in FIG. As explained in
For example, in a magnetic head unit with a two-channel stereo track configuration, only two tracks of one of the two channels are operated; in other words, the bias conductors of the tracks of other channels are not used. Therefore, the bias conductors of the MR magnetic head sections for the corresponding tracks of each channel are connected in series to substantially reduce the number of lines.

EXAMPLE The present invention will be described in detail with reference to FIG. 15. In this example, an analog stereo line consisting of left and right signal tracks I7 and R, respectively, has two channels ctH and ch.
This is the case when two truck configurations G are applied. In this case, each channel ch1
And each track L and R4 of ch2 to 4 MR magnetic nodes h1t, h1t+, h2L
h2. is provided, and each MRfa qi/nod part hl
L.

Regarding hIR, h2L, and h2r+, an MR magnetic sensing part (5) and a bias magnetic field 2 generating conductor (3
) is provided. In this configuration, corresponding tracks of channels ct+1 and ch2, that is, tracks R and R, are connected in series. In this way, the number of independent lines of the bias conductor, that is, the number of terminals, is the number of tracks in one channel, m,
In this example, there are only two terminals, TbL and TbR. Regarding each MR magnetic sensing part (5), each terminal T11
(Derivation of 1L, Tnu+, Tt+2L, TM2H) That is, the terminals of N channels are derived.

Then, a common terminal TC1, that is, one terminal, is led out from each other end of each line of each bias conductor (3) and each other end of each magnetically sensitive part (5).

Therefore, according to this configuration, the number of terminals is (m+
mN+1)...++ (21), and the above m=2. When N=2, that is, in a two-channel configuration with two tracks, there are seven terminals. Therefore, compared to the case described with reference to FIG. 14, the number of terminals can be reduced to two.

In other words, according to the configuration of the present invention, the above equation (20) and (21
) The number of terminals can be reduced by m(N-1), which is the difference between the equations (), and the greater the number of channels and the number of tracks for each channel, the greater the effect of reducing the number of terminals.

Effects of the Invention As described above, according to the present invention, the number of bias lines can be reduced;
Therefore, by reducing the number of terminals, it is possible to reduce the area occupied by the terminal section of the magnetic head device. It can bring many benefits such as making Sodotisop smaller and simplifying its structure.

[Brief explanation of the drawing]

FIG. 1 is an enlarged cross-sectional view of a magnetoresistive magnetic head device used to explain the present invention, FIG. 2 is a configuration diagram of a conventional magnetoresistive magnetic head device, and FIG. 3 is a diagram showing a magnetoresistive magnetic head device. FIG. 4 is a diagram of the characteristic curve of the magnetic part; FIG. 4 is a configuration diagram of an example of the magnetoresistive magnetic head device proposed earlier; FIGS. 5A and B are diagrams of its operating characteristic curve; 7 is a configuration diagram of another example of the magnetoresistive magnetic head device proposed earlier, FIG. 8 is a characteristic curve diagram for explaining the same, and FIG. 9 is a diagram of the magnetoresistive head device according to the present invention. 10 is a circuit diagram showing an equivalent circuit thereof, FIG. 11 is a waveform diagram for explaining the operation of the device in FIG. 9, and FIG. 12 is a diagram showing the device in FIG. 9. FIG. 13 is a configuration diagram showing another embodiment of the magnetoresistive magnetic head device according to the present invention, and FIG. 14 is a terminal lead-out wiring pattern diagram used to explain the present invention. , FIG. 15 is a wiring pattern diagram of an example of the device of the present invention. h is a magnetic head part, (11 is a substrate, (3) is a bias conductor, (5) is a magnetoresistive effect magnetic part, (7) and (8) are magnetic layers, (19) is a high-pass filter, ( 20) is a rectifier, (21) is a low-pass filter, (22) is a multiplier,
(23) are buffer amplifiers, TbL, TbR, TMI
L. TMIR, T112L, and 7M2R are terminals. U-1...- Fig. 5 R Fig. 6 Fig. 9 VD (t) Fig. 13 C1 S1 Page J Cd5 → Fig. 114 Fig. 15

Claims (1)

[Claims] Magnetoresistive magnetic heads corresponding to m tracks that operate simultaneously are provided for N channels.
In a magnetoresistive magnetic head device in which one channel out of N channels is selectively used, a conductor for generating a bias magnetic field of a magnetic head element for each corresponding track of each of the N channels is provided. A magnetoresistive magnetic head device comprising m independent bias magnetic field generating conductor lines interconnected in series.