JPS60263310A - Magneto-resistance effect type magnetic head device - Google Patents

Abstract

PURPOSE:To improve the rectilinearity and to increase a dynamic range by extracting a signal output corresponding to a signal magnetic field out of the output of a magneto-resistance effect type magnetism-sensitive part and applying a negative feedback magnetic field corresponding to said signal output to said magnetism-sensitive part to produce a negative feedback magnetic field. CONSTITUTION:The signal output given from an LPF21 is supplied to a buffer amplifier 23, and a current iFB is flowed to a bias conductor 3 from the amplifier 23. Thus the conductor 3 produces a negative feedback magnetic field HFB and gives it to an MR magnetism-sensitive part 5. As a result, the rectilinearity is improved more and the distortions are reduced less. This reduces the Barkhausen noises and increases a dynamic range. Thus the variance of output can be reduced.

Description

[Detailed description of the invention] Industrial applications The present invention relates to a magnetoresistive magnetic head device.

BACKGROUND TECHNOLOGY AND PROBLEMS First, with reference to FIG.
To explain an example of the structure of the head portion of a magnetic head device of type R), for example, Ni-Zn ferrite, Mn-
On a magnetic substrate (1) made of Zn-based ferrite or the like (via an insulating layer (2) of SiO2 etc. deposited on this substrate (if the substrate (11) has conductivity), as will be described later. A bias conductor +31 made of a strip-shaped conductive film that serves as a current path for generating a bias magnetic field to apply a bias magnetic field to the MR magnetic sensing part (5) is deposited, and an insulating layer is placed on the bias conductor (3). For example, Nl −F via (4)
An MR magnetic sensing part (5) made of an MR magnetic thin film such as an e-based alloy or a Ni-Co-based alloy is arranged. And this MR
A thin insulating layer (6) is placed on the magnetically sensitive part (5), with one end of each extending across the bias conductor (3) and the MR magnetically sensitive part (5), each forming a part of a magnetic circuit. For example, M as a magnetic core constituting the.

A pair of magnetic layers (7) and (8) of permalloy is deposited. A non-magnetic insulating protective layer (9) is formed on the substrate (11).
), the protecting group @ol is attached.

Therefore, a non-magnetic gap spacer layer (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 (11).
A front magnetic gap g is formed. Then, the front surfaces of the substrate +11, the gap spacer layer (11), the magnetic layer f71, the protective layer (9), and the protective substrate (10) are polished so that the magnetic gap g faces the magnetic recording medium such as a magnetic tape. A facing surface (12) is formed.

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 connected to the MR magnetic sensing portion (
5) A discontinuous portion (13) is formed between both ends of the discontinuous portion (13), which is formed so as to straddle the insulating layer (6). Although the rear end and the front end of the ceramic layers (7) and (8) are electrically insulated by the interposition of the insulating layer (6), they are not magnetically coupled at the discontinuous portion (13). It will be done like that. Thus, substrate (1) - magnetic gasop g
- Magnetic layer (71-MR) A magnetic circuit consisting of a closed magnetic path of R magnetic sensing part (5) - magnetic layer (8), one substrate + 11 is formed.

In such an MR type magnetic head section, the signal magnetic flux from the front gap g that is in contact with the magnetic recording medium flows through the above-mentioned magnetic circuit, thereby increasing the resistance of the MR magnetic sensing section (5) in this magnetic circuit. The value changes depending on the external magnetic field due to the signal magnetic flux.

Therefore, a detection current is passed through the MR magnetic sensing section (5), and this change in resistance value is detected as a voltage change across the MR magnetic sensing section (5), thereby reproducing the recorded signal on the magnetic medium.

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 in a state where a bias magnetic field He is applied by the magnetic field generated by applying the detection current IMH to the MR magnetic sensing part (5). Based on the resistance change caused by this signal magnetic field H3, the voltage across the MR magnetic sensing section (5), that is, the change in the potential at point A, is supplied to the amplifier (14) via the low-frequency blocking capacitor (16). The signal is then 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 this MR magnetic sensing part (5) and its resistance value R, and this curve shows the range where the absolute value of the magnetic field H is small -HBR~ 10HB
H 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 Rwin away from the quadratic curve. Incidentally, the maximum value Rwax 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 bone and the variation of the resistance of the MR magnetic sensing part (5). The resistance of the fixed bone is approximately 98%, and the temperature dependence of the fixed bone is large, so there is a drawback that the temperature drift of the electric potential at point A is large. This MR magnetic sensing part (
5) The resistance value R is R=Ro (1+a cos2θ)
---- (1) (where Ro is the fixed bone of the 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 (5)), For example, M.R.
Magnetic sensing part (5) is 81Ni-19Pe (permalloy)
The actual value of α in the case of an MR magnetic thin film with a thickness of 250 mm made of alloy is approximately 0.017. Although the value of α varies somewhat depending on the thickness and material of the MR magnetic thin film of the MR magnetic sensing part (5), it is approximately α=0.05 at most.

On the other hand, the fixed bone Ro of this resistance is Ro=R1(1+aAt)...(2+(However, R
i is the initial value of resistance, a is the temperature coefficient, and Δt is the temperature change), and the actual measured value of the temperature coefficient a in the example of the MR magnetic sensing part (5) described above is a = 0.0027. /
It is about 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 C required for 16) is as follows, (ωo=2πfo), where R is the resistance of the MR magnetic sensing part (5). Now, MR magnetic sensing part (5)
is made of the above-mentioned permalloy with a thickness of 250 mm and its length is 50 μm, its resistance R is about 120 Ω, so if f o = 1 kHz, the capacitor (16) is C = 1.3 μF. A large value is required, which is particularly problematic when constructing a multi-trunk type magnetic head device for digital audio signals.

In addition, it is desirable that 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, be as high as possible. Therefore, applying a bias magnetic field as described above will result in a decrease in magnetic permeability.

The above-mentioned DC bias type MR magnetic head device has the advantage of having a wide effective track width and being easily formed into a sandwich track, but has poor linearity, difficulty in DC reproduction, large sliding noise, and Barkhausen It has the disadvantages of high noise (and large output variations).

Other conventional MR magnetic head devices that have been proposed include a differential MR magnetic head device and a Barberball MR magnetic head device. A differential MR type magnetic head device is provided with a pair of MR magnetic sensing parts in its MR type magnetic head section, and the same bias magnetic field is applied to the pair of MR magnetic sensing parts by a common bias conductor. Differential output is obtained from the magnetic sensing part by the same signal magnetic field,
The differential output is 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 advantage of requiring only an amplifier as a 29 circuit with low Barkhausen noise and low output variation (with large off-cent variations), the effect of reducing sliding noise is small, the effective track width is narrow, and the The disadvantage is that it is difficult to trunk.

In addition, the barber pole type MR magnetic head device has its MR
This barber pole type MR type has a large number of mutually parallel conductor bars made of gold or the like, which are adhered to the MR magnetic sensing part of the magnetic head section so as to be diagonal in the longitudinal direction. Magnetic head devices have the advantage of having little Barkhausen noise, little variation in output, and only needing an amplifier as a circuit, but on the other hand, DC reproduction is difficult, sliding noise is large, it is difficult to make a sandwich track, and the effective track width is limited. The disadvantage is that it is not very spacious.

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 the previously proposed MR type magnetic head device will be described below with reference to FIG. In this example, the MR
The magnetic head section has the same configuration as explained in FIGS. 1 and 2, and in FIG. 4, the same reference numerals are given to the parts corresponding to those in FIGS. Omitted. In this example, a low-level AC bias current IA with a high frequency fC is superimposed on a DC bias current IB through the bias conductor (3) of the MR type magnetic head, and a high frequency A magnetic field is 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 Ha 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 H3 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 H3 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 MH
It is sufficient to select z. In this case, a high-pass filter (19
) has a low cutoff frequency higher than 100ktlz (,
And the frequency f C% shall be selected to be lower than I Ml (z, for example 500kllz).Then, the output of the high-pass filter is connected to the rectifier (20) as described above.
After rectification by, the cutoff frequency is 100kll.
By passing the signal through a low-pass filter (21) of 0 to 100 kHz, a signal in a band of 0 to 100 kHz is obtained at the output terminal (15).

In a magnetic head device having such a configuration, the sixth
The external magnetic field (signal magnetic field bias magnetic field) shown in Figure A is MR
When applied to the magnetic sensing part (5), at point B in Fig. 4, an output is obtained in which the carrier of frequency fc is amplitude-modulated with a signal, as shown in Fig. 6B, and as shown in Fig. 6C. Thus, at the output terminal (15), an output corresponding to the signal magnetic field is taken out.

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 magnetic 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 due to the above-mentioned sliding of the MR type magnetic head part with the magnetic medium can be reduced. It can be reduced.

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
6), the capacitance C should be 2600 pF. 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, no direct current bias current is caused to flow through the bias conductor (3), but only an alternating current bias current IA is caused to flow therethrough. FIG. 8 schematically shows this operation.

In this figure, the solid line curve is the operating characteristic curve of the magnetic field vs. resistance of the actual MR magnetic sensing part, but if the quadratic curve part of this characteristic is extrapolated, it becomes as shown by the broken line, and the minimum resistance value obtained by this is The magnetic field corresponding to Rll1in is +Ho and -H
o. In this example, an alternating current bias magnetic field 4 HA is applied superimposed on the signal magnetic field H9, and a resistance change of the MR magnetic sensing portion (5) corresponding to the polarity and magnitude of the signal magnetic field and in accordance with 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 magnetic sensing part (5) is expressed as follows.

Here, ΔRmax is ΔRmax = Rmax − Rm
It is given in. The magnetic field H applied to the MR magnetic sensing section (5) is expressed by the sum of the bias magnetic field HA(t) and the signal magnetic field Hs(tl) as shown in the following equation.

H (tl = HAit) +) (s (tl ” (5) where the magnetic field HA (t) is obtained by the current flowing in the bias conductor (3), HA (t) = HAO-sin (ωat) ・・・・
・(It is expressed as in 61. However, the angular frequency ωG is expressed as in the following equation.

ωc=2πfC (7) The output voltage V (t) of the MR magnetic sensing section (5) is as follows, where I is the MR detection current: 5 1tl=I ・ R (8) From the above equations (4), (5), and (6), it is expressed as follows.

X5in ωc ten (Hs (tl) 2)...(9
) Next, this output voltage V (tl and AC bias magnetic field H
A signal having the same wave number as A, for example, sin (ωat) is multiplied by a multiplier (22). Its output V z l
) is expressed as follows.

Vz (tl=V(t)・sin (al(Ht)+2
HAo−Hs(tl・sin (ωc t) +(Hs
(tl) 2) ・sin <6)c t)・・・0
1ll This is then passed through a low-pass filter (21) to
The term 1-Rnsax with ωC component in order αΦ
sin (alc t) =O”...(ID 6 HA♂・5irI2(ωat) HAO = −(sin (ωt) −cos (2ω1)Xs
in(ωt))=-0...(1ri2 HAO-H3Ttl ・5in2(ωt)=HA
o-Hs(ti(l-cos(2a+t))=H
AO-Hs (t) ”...(13)()(s (t
it 2・sin (ωt) −〇 ・・・(14)
becomes. Therefore, the output voltage Vo obtained at terminal (15)
(tl is ... (15), and a voltage proportional to the signal magnetic field HsTtl is obtained. In this case, the input to the multiplier (22) includes the signal magnetic field component Hs(tl). However, since there is little possibility that the high-pass filter (19) will be mixed into the output, the high-pass filter (19) can also be omitted.

According to such an MR type magnetic head device, it is possible to extract an output according to the polarity of the external magnetic field, and in addition to the same advantages as in the previous example, there is an advantage of a wide dynamic range. 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 the previously proposed MR type magnetic head device, it is possible to obtain output with excellent linearity and low distortion, DC reproduction is possible, temperature drift is small, sliding noise is improved, and the effective track width is widened. It has the advantages of being large, narrowing the track, and reducing the capacitance of the capacitor. Furthermore, when the configuration shown in FIG. 7 is used, the dynamic range can be widened; It is also possible to avoid a decrease in permeability of the magnetic circuit.

Object of the Invention The present invention provides a magnetoresistive magnetic head device in which an alternating current bias magnetic field is applied to a magnetoresistive magnetic sensing part.
The objective is to propose a system that further improves linearity, reduces distortion, reduces the occurrence of Barkhausen noise, further widens the dynamic range, and reduces variations in output 8.

Summary of the Invention A magnetoresistive magnetic head device according to the present invention includes: a magnetoresistive magnetic sensing section to which a signal magnetic field is applied; A signal extraction means for extracting a signal output according to the signal magnetic field from the output of the magnetic sensing section, and a negative feedback magnetic field generation means for applying a negative feedback magnetic field to the magnetoresistive magnetic sensing section according to the signal output from the signal extraction means. It is characterized by having.

According to the present invention described above, in a magnetoresistive magnetic head device in which an AC bias magnetic field is applied to a magnetoresistive magnetic sensing part, linearity is further improved, distortion is further reduced, and Barkhausen noise is reduced. It is possible to obtain a device with fewer occurrences of noise, a wider dynamic range, and less variation in output.

! EXAMPLE An example of the present invention will be described below with reference to FIG. This embodiment is a case in which the present invention is applied to the magnetoresistive magnetic head shown in FIG. 7. In FIG. 9, parts corresponding to those in FIG. .

That is, the signal output from the low-pass filter (21) is supplied to the buffer amplifier (23), and the current iFB from this is passed through the bias conductor (3).
(a separate bias conductor may also be provided, through which a current ipB flows) a negative feedback field HFB is generated,
so as to give it to the MR magnetic sensing part (5).

FIG. 10 shows an equivalent circuit of the magnetoresistive magnetic head device shown in FIG. 9, and shows the recording signal M of the running magnetic tape.
(Based on Xl, signal magnetic field Hs (tl, Hs
(tl = M(xi ・φm (j2π/λ)...
・(16) is generated, and the return magnetic field −Hpa(t)
occurs.

Thus, the output voltage V ftl from the MR magnetic sensing part (5) is V (tl-φh ・(Hs (tl-HpBf
tl) ...(17) is obtained. Also, signal extraction means (circuit (16)).

(19), (22), and (21)), the output signal 9 Vo (tl, Vo(t) = A (jω) ・Vltl - (1B) is obtained. Also, the feedback magnetic field - Hps (t ) is -Hps
It is expressed as (t)-K-A (jω) (19).

In addition, φm(j2π/λ) is the transfer function on the input side of the MR magnetically sensitive section (5) (where λ is the wavelength), φh is the 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 φi 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)
When a superimposed magnetic field of Tsftl is applied, the MR magnetic sensing part (5)
From this, an output voltage V Ttl as shown in FIG. 11C is obtained. In the multiplier (22), this output voltage V (t
) by the rectangular wave alternating current shown in Figure 11, the output side of the low-pass filter (21) has the following value:
Signal output Vo corresponding to f# magnetic field Hs(t) in Figure 1B
(t) 1 0 is output.

Next, Figure 12 shows the characteristics of second and third harmonic distortion of the signal output with respect to the recording level when a single frequency signal of 315 Hz is recorded on a magnetic tape and reproduced by various magnetic head devices. show. However, a metal tape was used as the magnetic tape. Tape speed is 4.7c+n/se
It was e. The recording magnetic head was a normal ring-shaped magnetic head. In the case of an MR type magnetic head device, its MR
The detection current iMR flowing through the magnetic sensing part (5) is 5 mA, the rectangular wave alternating current lA flowing through the bias conductor (3) is 5111^,
Its frequency was 250kHz.

Curve B2. B3 shows characteristic curves of second and third harmonic distortion of the output signal by the magnetoresistive magnetic head device of 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 222nd and 3rd harmonic distortion of the output signal from the magnetoresistive magnetic head device shown in FIG. 9, respectively, and curves A2 and A3
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 from a conventional ring-shaped magnetic head device shown in FIG.

Next, another embodiment of the present invention will be described with reference to FIG. This embodiment is a case in which the present invention is applied to the magnetoresistive magnetic head device shown in FIG. 4. In FIG. 13, parts corresponding to those in FIG. do. That is, the signal output from the low-pass filter (21) is supplied to the buffer amplifier (23), the current iFB from this is passed through the bias conductor (3), and the bias conductor (3) (separate bias conductor and a current i
A negative feedback magnetic field HFB is generated from the negative feedback magnetic field HFB and applied to the MR magnetic sensing section (5). For other explanations, the explanation of the embodiment shown in FIG. 9 is referred to.

According to the present invention described above, in a magnetoresistive magnetic head device in which an alternating current bias magnetic field is applied to the magnetoresistive magnetic sensing part, linearity is further improved, distortion is further reduced, and performance is improved. ``Ripatsu 57 noise generation is reduced,
It is possible to obtain a wider dynamic range and less variation in output.

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.

Effects of the Invention According to the present invention described above, in a magnetoresistive magnetic head device in which an alternating current bias magnetic field is applied to a magnetoresistive magnetic sensing part, linearity is further improved and distortion is further reduced. The generation of Barkhausen noise is reduced, the dynamic range is further widened, and output variations are reduced.

[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 3 proposed earlier, FIGS. 5A and B are diagrams of its operating characteristic curve, and FIG. 6 is a diagram of its operation. A waveform diagram for explanation, FIG. 7 is a configuration diagram of another example of the magnetoresistive magnetic head device proposed earlier, FIG. 8 is a characteristic curve diagram for explanation, and FIG. 9 is a diagram of the magnetoresistive head device according to the present invention. A configuration diagram showing an example of an effective magnetic head device, FIG. 10 is a circuit diagram showing an equivalent circuit thereof,
11 is a waveform diagram for explaining the operation of the device in FIG. 9, FIG. 12 is a characteristic curve diagram for explaining the characteristics of the device in FIG. 9, and FIG. 13 is a magnetoresistive magnetic head according to the present invention. It is a block diagram which shows another Example of an apparatus. h is a magnetic head part, (1) 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) is a buffer amplifier. 5 4 Figure 1 Figure 2

Claims (1)

[Claims] a magnetoresistive magnetic sensing section to which a signal magnetic field is applied, an alternating current magnetic field generation means for applying an alternating current bias magnetic field to the magnetoresistive magnetic sensing section, and a signal output according to the signal magnetic field from the output of the magnetoresistive magnetic sensing section. A magnetoresistive magnetic head comprising: a signal extracting means for extracting a signal; and a negative feedback magnetic field generating means for applying a negative feedback magnetic field to the magnetoresistive magnetic sensing part according to the signal output from the signal extracting means. Device.