JPS6187215A - Magneto-resistance effect type magnetic head device - Google Patents

Abstract

PURPOSE:To read a recording signal in the best state without varying sensitivity and linearity by an external magnetic field by controlling a current fed to an electric conductor with a detection signal from an external magnetic field detecting means and applying a specific bias magnetic field to an MR magnetism sensing part all the time. CONSTITUTION:The detecting means 20 for the external magnetic field which is arranged nearby a reproducing magnetic head element part 18 having an MR magnetic head element (h) is provided without contacting a magnetic medi um opposite. The detecting means 20 supplies specific detection currrents iS1 and iS2 to MR magnetism sensing parts 25 of elements hS1 and hS2 by a power source Vs while no external magnetic field is applied, and bias magnetic fields which provide maximum sensitivity are applied to respective fields which pro vide maximum sensitivity are applied to respective magnetism sensing parts 25 with respective magnetic fields generated by feeding the detection current. Consequently, the quantity of power feeding to the electric conductor 13 of a magnetic head part 18 for data track reproduction is controlled to eliminate variation of each bias magnetic field due to the unnecessary external magnetic field HN.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a magnetic head device (magnetic) 1 (anti-effect type magnetic head device).

[Conventional technology]

The magnetic head element of a magnetoresistive effect (hereinafter referred to as F'MR) type magnetic head device is, for example, as shown in FIG.
For example, a magnetic substrate made of Ni--Zn ferrite, Mn--Zn ferrite, etc. (11-h-, if this substrate 10 has conductivity, an insulating layer (2) of 5tO2 etc. A current-carrying conductor (3) that serves as a current path for generating a bias magnetic field that provides a bias magnetic field to a magnetic sensing section (hereinafter referred to as MR magnetic sensing section) having a magnetoresistive effect, which will be described later.
is provided. This current-carrying conductor (3) can be formed, for example, by a band-shaped conductive layer extending in one direction.Then, on this current-carrying conductor (3), an insulating layer (4) is interposed between the
An MR magnetic sensing part (5) made of an MR magnetic thin film of an i-Fe alloy or a Ni-Co wire alloy is arranged. One end of each straddles the MR magnetically sensitive part (5) via a thin insulating layer (6) and extends in a direction crossing the current-carrying conductor (3) and the MR magnetically sensitive part (5). A pair of magnetic elements 1e each forming a part of the magnetic core of the magnetic circuit.
A (7) and (8) are applied. A protective substrate 00 is connected to the substrate El) i via a non-magnetic insulating protective layer (9).
) are joined. A non-magnetic gap spacer (11) made of, for example, an insulating layer (6) and having a required thickness is interposed between one of the magnetic layers (7) and the front end of the substrate (1) to form a magnetic gap in the front. g is formed.

Then, place the substrate (1) so that this magnetic gap g is visible.
, gap spacer H (11), magnetic layer (7), protection! The front surfaces of i < 91 and protecting group & (101) are polished to form a surface (12) in contact with the magnetic recording medium.

Further, the rear end of the magnetic layer (7) constituting the magnetic gap g and the front end of the other magnetic layer (8) are respectively connected to the MR magnetic sensing part (
5) A discontinuous portion (13) is formed which is formed so as to straddle 1 with an insulating layer (6) interposed therebetween, but which extends between both ends and is spaced apart from each other. The rear and front ends of the internal magnetic j@+71 and (8) are provided with insulating layers (6) on both sides of the MR magnetic sensing part (5), respectively.
Although they are electrically insulated due to the intervention of are connected to the substrate +11-magnetic core g-magnetic layer +7+
-M R magnetically sensitive g++ (51-magnetic layer (8)-substrate (1
) is formed. In such an MR type magnetic head, the signal magnetic flux due to the recording signal recorded on the magnetic medium flows through the above-mentioned magnetic circuit from the magnetic gap g that is in contact with the magnetic medium, thereby increasing the MR magnetism in the magnetic circuit. Since the resistance value of the section (5) changes according to the external magnetic field caused by this signal magnetic flux, this change in resistance value is detected by passing the detection current i MR through the MR magnetic sensing section (5). The recording signal on the magnetic medium is reproduced by detecting the voltage change at both ends of the magnetic medium.

The magnetic ttb resistance characteristics of this MR magnetic sensing part are shown in FIG. In this way, the magnetoresistive characteristic curve of the MR magnetic sensing part (5) is
Within the magnetic field range of ζ, the quadratic curve is blurred, and therefore, its sensitivity characteristic exceeds the maximum ifi at two values of the magnetic field, as shown in FIG. The point at which this sensitivity is maximum is also the point at which linearity is excellent. Therefore, in this type of magnetic head, a bias magnetic field T (B) is applied to the MR magnetic sensing portion (5) in the vicinity where maximum sensitivity is obtained.

This bias magnetic field He is mainly applied to the above-mentioned current-carrying conductor (
3) (external bias magnetic field caused by the magnetic field induced by the current flowing to The generated magnetic field is also given by the addition of HMR.

That is, this type of MR type magnetic head device, as shown in FIG. 5. to the MR magnetic sensing part (5). At the same time, a predetermined detection current inR is applied to this MR magnetic sensing part (5), and in this state, the magnetic field HBO generated by energizing the current-carrying conductor (3) is applied to the MR magnetic sensing part (5). and the magnetic field HMR generated by applying the detection current iMn to the MR magnetic sensing part (5), while applying a bias magnetic field He.
The signal magnetic field Hs from the magnetic medium mentioned above is given, and based on the resistance change due to this signal magnetic field Hs, <M
The change in the voltage across the R-sensitive magnetic section (5), that is, the potential at point A, is amplified by an amplifier (14) and detected from the output terminal (15). (16) is a low frequency blocking capacitor.

[Problem that the invention seeks to solve]

As mentioned above, in the MR type magnetic head, the MR
The operating point is set at an operating point where good sensitivity and linearity can be obtained by applying the required bias magnetic field HH to the 5 magnetic parts. When an unnecessary external noise magnetic field HN other than the output magnetic field is applied, for example, a magnetic field generated from a motor etc. (hereinafter referred to as external magnetic field), the actual setting state of the bias magnetic field for the MR magnetic sensing section changes. This changes its sensitivity and linearity, causing distortion and noise in the reproduced signal.

Now 1. For the MR magnetic head element having the characteristics explained in FIGS. 13 and 14, an external magnetic field HN is applied in the width direction of the strip-shaped MR magnetic sensing part, HH=0 (Oe), respectively.
HN-+ 10 (Oe), HN =-10 (Oe)
Figure 16 shows the sensitivity curves for each case. still,
In this Fig. 16, the reason why the sensitivity characteristic curve of Hu -0 (Oe) does not pass through the 10000 point is due to the magnetic field generated by the 1ffJ current to the current-carrying conductor, that is, the bias current ieo, as mentioned above. This is due to the effect of the magnetic field HHR caused by the detection current i MR flowing to the MR magnetic sensing section.

[Problem that the invention seeks to solve]

As mentioned above, in the MR type magnetic head, the influence of unnecessary external magnetic field H poses a problem.

In the present invention, the M
An R-type magnetic head device is provided.

[Means for solving problems]

In the present invention, ζ is the magnetoresistive effect (M
In an MR type magnetic head device, the MR type magnetic head device has a magnetic head element section that reproduces a recorded signal on a magnetic recording medium, and includes a magnetic sensing section having a magnetic field R) and a current-carrying conductor that generates a high-speed magnetic field in its dirt. , an external magnetic field detecting means is provided in a position close to the magnetic head element but not in contact with the magnetic recording medium, and the upstream of the energization of the current-carrying conductor is controlled by the detection signal from the external magnetic field detecting means to constantly provide MR sensing. A predetermined bias magnetic field is applied to the magnetic part.

[Effect]

As described above, in the present invention, an external magnetic field detection means is provided, and the detection output is used to apply a predetermined bias magnetic field to the MR magnetic sensing section. It is possible to reliably read signals recorded on a magnetic medium under the best conditions without causing any fluctuation in linearity or linearity.

〔Example〕

An example of an MR type magnetic head device according to the present invention will be explained with reference to FIG. In this example, the corresponding (
- A multi-trunk type data track reproducing magnetic head element section (18) is provided in which a plurality of MR magnetic head elements for reproducing the signal magnetic field on the rack, that is, the recorded signal, are arranged. Each magnetic head element can have the same structure as explained in FIG. 12, but each element is formed between a common substrate (1) and 00. Then, this data trunk reproduction magnetic head element section (18
) can be constructed by providing on the substrate (1) a strip-shaped conductive film extending across the bottom of all the MR magnetically sensitive parts (5) of all the elements.

In FIG. 1, (17) is a current source that obtains the detection current iMR to each MR magnetic sensing part (5) explained in FIG. 15, respectively;
Furthermore, a circuit for extracting the reproduction output from each magnetic sensing part (5), that is, a capacitor (16) attached to each magnetic head element.
), amplifier (14), and other circuit parts are removed as a whole. In particular, in the present invention, the reproducing magnetic head element section (18) having the MR magnetic head element is
An external magnetic field detection means (20) is provided at a position close to the magnetic medium but not in contact with the magnetic medium.

This external magnetic field detection means (20) is, for example, a pair of MR magnetic heads for detecting external magnetic fields, which have the same configuration and characteristics as each magnetic head element of the reproducing magnetic head section (18).
It can be formed from elements hs1 and hS2.

These elements hs1 and hs2 are the magnetic substrate fl (for example, described in FIG. 12) on which the magnetic head element section H is constructed.
and a protective substrate aω. The detecting means (20) is arranged as close as possible to the reproducing magnetic head element section (18) so that it can receive the same external magnetic field H.
) is placed in a position where it does not come into contact with the magnetic medium. (25) corresponds to the MR magnetic sensing part (5) of the magnetic node element in each MR magnetic sensing part of each element hst and hS2, and (23) corresponds to the MR magnetic sensing part (25) of each element hst and hS2.
) is a schematic illustration of the current-carrying conductor provided across the bottom of these magnetic sensing parts (25) in order to apply a common bias magnetic field to the magnetic head part (18). This corresponds to the current-carrying conductor (3).

Each of the sensing MR magnetic head elements hS1 and hS2 has one end grounded, and the other end connected to each input side of the differential amplifier (21), respectively, and connected to a common power source ■s.
connected to each MR magnetic sensing part (2) of each element hs1 and hS2.
5) With respect to the common external magnetic field Ha to be detected, the detection currents are in opposite directions.

is2 is passed through. and differential amplifier (21)
The output of
It is superimposed on so and is supplied to the conductor (3). On the other hand, a part of the output of the differential amplifier (21) is supplied to a current triher (24), and the output current from this is supplied to the iin conductor (23).

In such a configuration, when the external magnetic field 11N is not applied and the required detection current iMn is applied to each MR magnetic sensing part (5) of the data track reproduction magnetic head element part (1st), From the current-carrying conductor (3), each part (5)
Optimum sensitivity and curve characteristics can be obtained for DC bias (t3').
Set the bias current iso that can be obtained every 5 times the field HRO. On the other hand, in the same way, in the state where no field is applied, predetermined detection currents is1 and is2 are applied to the MR magnetic sensing parts (25) of each element hs□ and hS2 by the power supply ■s in the detection means (20). and to energize this detection current,
The convex sensitivity of each magnetic sensing part (25) is set so that it can be increased by 1 from the bo-field bias magnetic field by each magnetic field generated by 1. In addition, in this configuration, the external magnetic field H,
In a state where the output current cannot be obtained, the output from the differential power increaser (2I) is set to, for example, 0, so that no output current can be obtained from this, and the read magnetic head element section (18) is Only the above-mentioned predetermined bias current iso is applied to the current-carrying conductor (3) so that a predetermined sensitivity can be obtained.

In this state, when a common external magnetic field H is applied to the magnetic head element section (18) and the detection means (20), each element hst and hs2 of the detection means (20) is affected by -2.
The output from the differential vii circuit (21) is obtained by the output from the differential circuit (21). The output of each is supplied to a current driver (22), from which a cancellation current ip for canceling the influence of the external magnetic field according to the external magnetic field 1-IN is obtained. That is, by supplying a cancellation current 1 day superimposed on the bias current iBO mentioned above to the 1FFI conductor (3) of the magnetic head element section (18) for data track reproduction, the external magnetic field H, This cancels fluctuations in the magnetic field applied to each MR magnetic sensing part (5) of each magnetic head element.

On the other hand, part of the output from the differential amplifier (21) is introduced into the current driver (24), and the current obtained from this is applied to the current-carrying conductor (23) of the detection means (20). The influence of the external θ field HH on each magnetic sensing portion (25) of this means (20) is canceled.

In the example shown in Figure 1, each MR magnetic head element, hS
In the case where a DC bias magnetic field is applied to each of l and hsy, a bias magnetic field in which an AC bias magnetic field is superimposed on a DC bias magnetic field is applied to these MR magnetic head elements, or an AC bias magnetic field is applied to these MR magnetic head elements. I can do anything.

In this way, when applying an alternating current or a bias magnetic field in which alternating current is superimposed on direct current to the MR magnetic sensing part, MR(a
This makes it possible to reduce the temperature dependence of the optical head element, improve linearity, and reduce distortion. First, this will be explained in detail. On the other hand, the configuration in which an alternating current bias magnetic field or a bias magnetic field obtained by superimposing an alternating current on a direct current is applied to the MR magnetic sensing part was proposed in Japanese Patent Application No. 1983-38980 filed by the present applicant. be.

That is, considering the operating characteristics of the MR magnetic sensing part (5) again with reference to FIG. , a signal magnetic field is applied from the magnetic medium indicated by the symbol (26) in FIG. There is ζ.

However, in this case, the larger the magnitude of the signal magnetic field is, the larger the secondary west-key gL run becomes.

In addition, the electric potential (S) at point A in FIG. 15 in the above-mentioned MR type magnetic head device is determined by the combination of the fixed resistance and the variable resistance of the MR% magnetic section (51 (25)). In this case, the fixed portion is about 98%,
Since the fixed portion of this resistance has a large temperature dependence, there is a drawback that the potential at point A drifts by degrees i'fA. The resistance value R of this MR magnetic sensing part is R=Ro (1+cx cns2θ) ・-
1ll (where Ro is the fixed resistance, α is the maximum resistance change rate, and θ is the angle between the current direction and the magnetization direction in the MR magnetic sensing part). For example, if the MR magnetic sensing part is 8
Thickness 250 by 1N 9Fe (permalloy) alloy
The actual measured value of α in the case of a human MR magnetic thin film is α−0,
It has a culm degree of 017. The value of α is MR magnetic M! Although there are some differences depending on the membrane thickness and material of the gland, it is approximately α-0.05 at most.

On the other hand, this Ro is Ro = Ri (1+aΔt)...(
21 (Please note that R4 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 above-mentioned MR magnetic sensing example 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 MRR magnetic head element,
As mentioned above, since its temperature coefficient is large, for example, M
Energization to R magnetic sensitivity or bias energization conductor +31 (
If the temperature of the head changes due to unstable heat dissipation due to heat generated by bias current or the like applied to the magnetic medium by sliding contact between the head section and the magnetic medium, large noise, so-called sliding noise, will be generated.

Furthermore, if the amplifier (14) in the configuration shown in FIG. 15 has a low impedance input, and the cutoff frequency of the capacitor (16) is fo, then
The required stitch C is as follows: Cfu□-...(3) Rω 0 (ωo=2πfo). Now, the MR magnetic sensing material is made of permalloy with a thickness of 250 mm and a length of 50 mm.
If it is μm, the resistance value R will be about 120Ω, so if fo-1kHz, a large value of C=1.3μF is required, which is a problem especially when constructing a multi-track type magnetic head element section. It is what it is.

In addition, the magnetic permeability in the magnetic circuit, especially in the magnetic layers (7) and (8) which are relatively thin and have a small cross-sectional area, is
It is desirable that this be a human body as much as possible, and since this magnetic permeability is at its maximum when the external magnetic field is zero, applying a bias magnetic field as described above will result in a decrease in magnetic permeability.

Elimination or improvement of these various drawbacks can be achieved by the configuration described below.

That is, as shown in Fig. 2, a high-frequency magnetic field is applied to the MR sensing conductor (31 (23)) of the head element by passing an AC bias current i^ with a small MJ frequency fc superimposed on a DC bias current iso. 51 (25) to the magnetic field.Here, the waveform of the AC bias current i^, and thus the waveform of the AC magnetic field, does not matter whether it is a +E string wave, a rectangular wave, etc.In this way, MR magnetic sensing Since an AC bias magnetic field superimposed on a DC bias magnetic field is applied to the MR sensor, an AC signal with a frequency fc is extracted between both ends of the MR magnetic sensor, that is, at point A in FIG. 2.A in FIG. The external DC bias magnetic field 1 (R,) applied to the MR magnetic sensor from the outside by the DC bias current ieo of -, and the self-bias magnetic field H generated by the detection current to the MR magnetic sensor
The total DC bias magnetic field H)1 resulting from the sum of HR and AC bias magnetic field HA due to the AC current iA is applied to the signal magnetic field H8 by 1t. 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 curve in FIG. In other words, since it is a derivative of a quadratic curve, as shown in FIG. 3B, the total DC bias magnetic field 14B and No. 16 magnetic field H
In principle, the change in resistance, which is the output, is a straight line with respect to the magnitude of S. Therefore, the magnitude of the AC signal that is 1% added to point A in FIG. 2 becomes an output that changes in accordance with the total DC bias magnetic field HB and the change in phase of the signal magnetic field from the magnetic recording medium. As shown in Fig. 2, this output passes through the above-mentioned frequency component [C, passes through the narrow pass filter (30), is rectified by the rectifier (31), and passes through the low pass filter (32). In this way, an output corresponding to the signal magnetic field from the magnetic medium can be obtained.

In this case, the frequency fc of the alternating current crystal is such that the band of output finally obtained from the output terminal (15) is 0 to 100k.
If llz is necessary, it may be shifted to a sufficiently lower frequency than this, for example, rc-IMh. In this case, the plane pass filter (30) has a low cutoff frequency of 100k) which is lower than Iz, and is lower than fc, for example IMIIz, for example 50k.
0K) Iz. Then, the output from this is rectified by the rectifier (31) as described above, and then passed through the low-pass filter (32) with a cutoff frequency of 100 Hy. If it is 4 like this, it is O~10
A signal in the 0Ktlz band is obtained.

4. That is, in a magnetic head device with such a configuration, when the magnetic field shown in FIG. In! In the case of jλB, as shown in Fig. 4B, an output is obtained in which the key real estate of the frequency [C is changed by 1 by the signal, and the output terminal (1
In step 5), an output corresponding to the signal magnetic field Hs is extracted.

In this way, an output with a linear operating characteristic corresponding to the differentiation of the original quadratic curve operating characteristic of the MR magnetic sensing section is obtained, so a reproduced signal without distortion can be obtained. .

Furthermore, as mentioned above, even if the fixed resistance of the MR magnetic sensing section has a large temperature dependence, this configuration is based on the characteristics obtained by differentiating the operating characteristic curve of the MR magnetic sensing section. Depends on the fixed amount! 11: can be eliminated, and temperature drift can be significantly reduced.

Additionally, as mentioned above, noise caused by sliding with the magnetic medium can be improved by eliminating the temperature dependence of the fixed resistance of the MR magnetic sensing section (1).

Also, since the capacitor (16) can only pass the frequency fc, for example, if f c = 500KHz, the capacitance C of this capacitor (16) is C = 1600pF.
It will be a good thing. And if you send this rc to history,
Its size, 9C, can be made smaller than ever before.

FIG. 145 is a block diagram of another example in which an AC bias is used. In this example, only an AC bias current is supplied to the current-carrying conductors (3) (23). 4 in Figure 5
Portions corresponding to those in the figures are designated by the same reference numerals and redundant explanation will be omitted. FIG. 6 is an operating characteristic curve diagram in this case. In this figure, the solid line curve (61) is the actual R-H operating characteristic curve, but if the quadratic curve part of this characteristic is extrapolated, it becomes as shown by the broken line, and the minimum resistance value Rmi
The magnetic field is 1 HO and -1 (o) without n. As shown in Fig. 6, in this example, an alternating current bias magnetic field 11^ is superimposed on the signal magnetic field Hs. MR according to the AC bias magnetic field depending on the magnitude of the magnetic field
Changes in resistance of the magnetically sensitive part can be obtained.

In this case, the MR operating characteristic curve is a quadratic curve, and the resistance value RMR of this MR magnetic sensing part is expressed as follows.

For example, ΔRmax - Rmax - Rmin.

Here, a magnetic field H is applied to the MR magnetic sensing section. This magnetic field H
is the AC bias magnetic field H^ (11) and the signal magnetic field H5 (tl
It is expressed as the sum of That is, H(tl= HA (t)+ Hs (jl
--・+5) Here HA (11 is a current-carrying conductor (31
(23) and 1((tl Hp, ・5in(ωc t)
・-・(Set to 61.Here ωC−2πfc ・・・(7)M
The output V ttl of the R magnetic sensing part is V(tl −i Mn−RsR...(8) where the MR detection current is inR), and from the above equations (4), +5), +6), it can be calculated as follows: is expressed in

ΔRmax V(t)-i HR-Rmax'x-i MR・-Ho
' X (I(AO2・sin' (L) t +2HA
O−H3(tlXsin(ωL)+(H3(11)J
・−−+c+) Next, V ttl and a signal of the same phase and frequency as the AC bias magnetic field I (^, e.g. sin
(ωt) is multiplied by a multiplier (52). Its output V z ft) is V z (tl is V z (t)=Vltl・sin (ωt)=
iHB-Rmax-sin(ωt)+2+1AO-H
s(tl ・sir+ (ωt )+ (Hs (tl
)21 ·sin (ωL) ···−(101) Then, when this is passed through the low-pass filter (32), the term having the ω component in 200) is eliminated. ZunawajiHR-Rmax -sin (ωt) →0 -・・
(If)HAO' ・5in2(ωl) xsin(ω1)) →0 ・・・ (12
)2tlA□-Hs(t) ・5in2(ωt)=HA
O・)(S(ti (t −cos(2ωt)1→H
Ao-Hs (t)...(13) (Hs (t)) ' ・ sin (ωt) → 0 ・
...(14) Across the range, the output voltage Vofl) obtained at the terminal (15) is Voft)-jMR'ΔRmax, and a voltage proportional to the signal magnetic field H8(t) is obtained. In this case, the signal magnetic field component H5 (tl
Even if it is included, it does not appear in the output, so the high-pass filter (30) is not necessarily required.

According to the above-mentioned configuration, it is possible to output an output according to the polarity of the external magnetic field, and in addition to the same advantages as the example shown in FIG. 2, there is an advantage that the dynamic range becomes large. Further, in this case, there is an advantage that by using only the alternating current component as the magnetic bias, it is possible to avoid low permeability of the magnetic circuit due to the direct current bias.

Figure 7 shows the °C1 external magnetic field detection means (
20), when the AC bias method explained in Fig. 5 is adopted, and in this case, the MR magnetic head element for detecting the external magnetic field is the difference between the pair of MR magnetic head elements as explained in Fig. 1. A single MR& can be configured by a simple head without using a dynamic configuration.
There is C. In FIG. 7, parts corresponding to those in FIGS. 1 and 2 are designated by the same reference numerals, and redundant explanation will be omitted.

In this case, a differential amplifier (70) is provided on the output side of the external magnetic field detection means (20), and this
With the adjustment in step 1), the MR magnetic head element between the magnetic head element section (18) of the data track and the external magnetic field detection means (20) is adjusted in a state where no external magnetic field H is applied.
It is set so that a required bias current iBo is applied to each of the 1llll conductors (3) and (23) of s. (
73) is an adder in which a part of the output current from the differential amplifier (70) is added to the AC bias current from the AC bias power supply (73) of frequency fc, and the result is applied to the current-carrying conductor (23). (74) and (75) are resistors provided in each current supply path of each current-carrying conductor (31 and (23)), which set the output from the differential amplifier (70) to a predetermined ratio. let

According to such a configuration, when an external magnetic field H is applied, a corresponding output is taken out from the magnetic head element hs of the detection means (20), and the output from the differential amplifier (70) is output from the external magnetic field H. An output current corresponding to the variation in HH is obtained, and this is supplied to the current-carrying conductor (3) of the data track reproducing magnetic head element section (18) and the current-carrying conductor (3) of the magnetic head element hs of the detection means (20). 23) is fed or foot hacked. In this way, it is possible to cancel the fluctuations in the actual bias magnetic field caused by the external magnetic field HN to each magnetic head element and the magnetic sensing parts (3) and (23) of IIs.

In the example shown in FIG. 7, the output from the differential amplifier (70) is feed-hacked to the magnetic head element hs for detecting an external magnetic field, but in the example shown in FIG. When the amplifier (70) itself is provided with a gain adjustment means (76) based on its own output, the feedback path for the above-mentioned element hs can be omitted. In FIG. 8, parts corresponding to those in FIG. 7 are designated by the same reference numerals, and redundant explanation will be omitted.

Moreover, FIG. 9 shows still another example of the device of the present invention,
Parts corresponding to those in Fig. 7 are given the same reference numerals.

Although redundant explanation will be omitted, in this example, in the external magnetic field detection magnetic head element hs of the external magnetic field detection means (20), a current-carrying conductor that applies an AC bias magnetic field to the MR magnetic sensing section (25) is used. In addition to (23a), the current-carrying conductor (3) in the magnetic F' element for data track reproduction
A current-carrying conductor (23b) is provided extending from the MR 13 magnetic part (25), thereby canceling out bias fluctuations caused by the external magnetic field H on the MR 13 magnetic part (25). If this is done, the magnetic head element h
That time of feet hassoku for s; Raku can be omitted.

In this case, the magnetic head element hs for detecting an external magnetic field is
As illustrated in FIG.
). In FIG. 10, parts corresponding to those in FIG. 12 are designated by the same reference numerals (repeated explanation will be omitted).

FIG. 11 is a block diagram showing another example in the history of the device of the present invention. In this example, the MR magnetic head element of each track of the data track reproducing magnetic head element section (1B) is also In the case where a configuration in which the bias magnetic field can be changed is adopted, parts in FIG. 11 corresponding to those in FIG. 7 are given the same reference numerals and redundant explanation will be omitted. (77) in the figure indicates each M
This is an output circuit provided corresponding to the R magnetic head element and hs.

Further, in this example, the current-carrying conductor (23) of the external magnetic field detecting means head element hs is extended from the current-carrying conductor (3) of the data track reproducing magnetic head element section (IH) to be electrically common. This is the case when configured.

〔Effect of the invention〕

As mentioned above, in the present invention, an external magnetic field under almost the same conditions as the magnetic field 671 (18) for data trunk reproduction, as well as an unnecessary external noise magnetic field HN, can be received in the vicinity of the magnetic section 671 (18) for data trunk reproduction. , an external magnetic field detection means (20) is provided, whereby the data track reproducing magnetic head section (
The energization P to the current-carrying conductor (3) of 18) is controlled to eliminate fluctuations in the bias state caused by unnecessary external magnetic fields H, so that the best results for 8' It is possible to operate in a stable state with sensitivity and linearity of .

[Brief explanation of drawings]

FIG. 1, FIG. 7, FIG. 8, FIG. 9, and FIG. 11 are respective configuration diagrams of a magnetoresistive magnetic head device according to the present invention, and FIG. 2 is a bias magnetic field supply for explaining the same. A block diagram showing an example of the mode and output circuit, FIG. 3 is an operation diagram for explaining the mode, FIG. 4 is a diagram for explaining the mode, and FIG.
The figure shows another example of the supply mode of the bias magnetic field and the output circuit.
The figure is an enlarged linear cross-sectional view of a magnetic head element for detecting an external magnetic field, FIG. 12 is an enlarged linear cross-sectional view of an example of a magnetoresistive magnetic head element, and FIGS. 13 and 14 illustrate the operation thereof A characteristic curve diagram and a sensitivity characteristic curve diagram; FIG. 15 is a block diagram showing the configuration of a conventional magnetic head device;
FIG. 6 is a sensitivity characteristic curve diagram for explaining this. (18) is a magnetic head element section for data track reproduction;
h is the MR magnetic head element, l(, is the external magnetic field, (20)
, hSt and hsy are MR magnetic head elements for external magnetic field detection, (5) and (25) are MR magnetic sensing parts, (31, (23), (23a) and (23) is a current-carrying conductor, (16) is a DC 1F capacitor, (31) is a rectifier, (21) and (71) are differential amplifiers, (30) is a high-pass filter, (32) is a low-pass filter, (52) is a multiplier, and (73) is an AC' power supply.
t-------- External 76 Rokuhaya 5j [l/-25---MR stone eaves 1l120-
・-・--Ichigo; L number 2f-----fi motion 4? ! Toga JO---Number of tomorrow-1M village barri J2 ・-
・---1hZkJu! L1tt letter 52・---
-・- Heavy N! ! # 70 -----1 differential tank W calendar 71 ------- Off (cut f stage 72 --------11rJ 11 Figure 72' Figure 13 Figure 14 Figure 15 Figure 16

Claims (1)

[Claims] It consists of a magnetic head element section that is equipped with a magnetic sensing section having a magnetoresistive effect and a current-carrying conductor that applies a bias magnetic field to the magnetic head element section and that reproduces recorded signals on a magnetic recording medium, and means for detecting an external magnetic field. A magnetoresistive magnetic head device, wherein the bias magnetic field is controlled by controlling the current flowing through the current-carrying conductor based on the detection output of the magnetoresistive magnetic head device.