JPH07334823A - Mr characteristic measuring instrument - Google Patents

Abstract

PURPOSE:To obtain an instrument which is capable of measuring the electromagnetic conversion characteristics, such as MR characteristic and frequency characteristic of an MR element without requiring slider working and mounting on a gimbal plate. CONSTITUTION:This MR characteristic measuring instrument is an instrument to evaluate the electromagnetic conversion characteristic of the MR element disposed in an MR/IND head and has an AFM/MFM 12, a magnetic field impressing medium 14 having a magnetic reference mark 26 at the top end face, a first positioning device 16 and a second positioning device 18. The first positioning device 16 has an imposing surface 24 and places the MR/IND head on the imposing surface by aligning the central axis of the MR element with the Z direction of the three-dimensional coordinate system of which X direction and Y direction are the track width direction and thickness direction of the MR element, respectively and positions the MR/IND head by freely moving the head in the X-, Y- and Z directions. The second positioning device positions the magnetic field impressing medium by freely moving the medium in the X-, Y- and Z directions while holding the magnetic field impressing means by aligning its magnetic field direction with the Z direction. The AFM/MFM is a microscope commonly used for interatomic force and magnetic force to obtain the information on the ruggedness of a surface and the information on magnetism.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for measuring MR characteristics, and more particularly to an M / N head incorporated in an MR / IND head.
The present invention relates to a device for measuring the electromagnetic conversion characteristics of an R element.

[0002]

2. Description of the Related Art With the increase in recording density and the narrower track of magnetic recording, M has been used as a high-density read head for magnetic recording.
The R head has been widely used. MR
The head uses a magnetoresistive effect element (hereinafter simply referred to as an MR element) that exhibits a magnetoresistive effect phenomenon in which the electric resistivity changes due to the presence of a magnetic field, and the electric resistance that changes depending on the presence or absence of magnetic flux of the magnetic recording medium is used. By detecting, the magnetic information written on the magnetic recording medium is reproduced.

The MR / IND head is a write / read head using an inductive head on the write side and an MR head on the read side.
As shown in the perspective view of FIG. 1, the inductive head A is configured to face the MR head B, and the inductive head A has an upper core C made of a soft magnetic material.
And a recording coil D and an upper shield E made of a soft magnetic material, and a gap is provided between the upper core C and the upper shield E. On the other hand, the MR head B is composed of an MR element F, a substrate G, and a lower layer shield H formed on the substrate G. In this specification, the X direction and the Y direction
A three-dimensional coordinate system whose directions are the track width direction and the thickness direction of the MR element is used.

The electromagnetic conversion characteristics of the MR element of the MR / IND head, including the magnetoresistive effect characteristics (hereinafter referred to as MR characteristics), reproduction characteristics, off-track characteristics, reproduction stability due to the recording magnetic field, etc. It was evaluated by detecting the magnetic signal recorded on the hard disk with an MR element. FIG. 2 is a graph of the MR characteristic curve of the MR element, in which the horizontal axis shows the magnetic field strength and the vertical axis shows the output signal (voltage) of the MR element. In FIG. 2, the solid line C1 is the MR characteristic when the bias magnetic field is not applied to the MR element, and the broken line C2 is the MR characteristic when the bias magnetic field is applied to the MR element.
The output signal of the MR element is represented by the difference Vd between the signal voltage when the magnetic field strength is 0 and the signal voltage when the magnetic field strength is an arbitrary magnitude. The bias magnetic field is a magnetic field applied in a direction orthogonal to the sense current so that the angle formed by the sense current flowing through the MR element and the magnetization of the MR element becomes a predetermined angle, preferably 45 °. By obtaining this MR characteristic curve, the above electromagnetic conversion characteristics can be evaluated.

[0005]

However, this magnetic signal recorded on the hard disk is very weak, and due to the recession between the head and the substrate, which is inevitable when the MR / IND head is processed, It was difficult to establish a correlation between the MR characteristics of the MR element itself and the MR characteristics of the MR element when actually used as an MR / IND head, and the reliability of evaluation was low. Further, in order to evaluate by this method, it is necessary to process the MR / IND head with a slider and attach it to the gimbal plate, so the MR element provided in the MR / IND head product is
The evaluation is possible only after a long time has passed since the wafer was manufactured. As a result, it is difficult to grasp the manufacturing yield of the head and to feed back the product improvement information to the designer, which makes it difficult to improve productivity or improve the structure and function of the head.

Therefore, as a method for quickly grasping the MR characteristics of the head, a magnetic force microscope (Magnetic Force Micros
cope, MFM) and changing the magnetic field strength emitted from the probe to measure the MR characteristics of the MR element. With this method, it is not necessary to process the slider on the head and attach it to the gimbal plate for measuring the MR characteristics, but there are the following three problems from the measurement principle. First and foremost,
Since the magnetic field intensity emitted from the MFM probe is low, only a part of the resistance change characteristic of the MR element can be measured.
Secondly, since the tip of the MFM probe is as small as several tens of nanometers, its size is physically different from the actual recorded signal, and therefore the reliability of the measurement result is low. . Thirdly, since the magnetic field emitted from the MFM probe has no spatial directivity, the frequency characteristic of the MR element cannot be measured.

In view of the above-mentioned problems, it is an object of the present invention to provide a highly reliable electromagnetic conversion characteristic including MR characteristics and frequency characteristics of an MR element without requiring slider processing and attachment to a gimbal plate. It is to provide a device that can be measured by.

[0008]

In order to achieve the above object, an MR characteristic measuring apparatus according to the present invention is an apparatus for evaluating the electromagnetic conversion characteristic of an MR element in an MR / IND head. The MR / IND head is mounted with the central axis of the MR element oriented in the Z direction of the three-dimensional coordinate system in which the Y direction is the track width direction and the thickness direction of the MR element, and the MR / IND head is freely movable in the X direction, the Y direction, and the Z direction. A first positioning device for moving and positioning, a magnetic field applying medium having a magnetic reference mark for positioning on the upper end surface and forming a magnetic field with variable magnetic field strength, and holding the magnetic field direction in the Z direction. A second positioning device for freely moving and positioning the magnetic field applying medium in the X direction, Y direction and Z direction, and for both atomic force and magnetic force for scanning the surface with a probe to obtain surface irregularity information and magnetic information Equipped with a microscope The probe is operated while moving the first positioning device and the second positioning device with reference to the reference mark of the magnetic field applying medium, and from top to bottom, the probe, the magnetic field direction of the magnetic field applying medium, and the center of the MR element. It is characterized in that it is positioned so as to coincide with the axis, and then the magnetic field strength of the magnetic field applying medium is changed to measure the electromagnetic conversion characteristics of the MR element.

The atomic force and magnetic force microscope used in the present invention is an atomic force microscope (Atomic F) capable of detecting fine irregularities on the surface by utilizing the atomic force on the surface of a probe and an object.
(orceMicroscope, AFM) and a magnetic force microscope (MFM) that detects a magnetic distribution of a minute portion by detecting a fine magnetic force, and is a known device. First and second
The positioning device is a known device that stores the positioning information of the positioned object in XYZ coordinates and the like, and can further move the object to the set position based on the stored positioning information.

Another MR characteristic measuring apparatus according to the present invention is an apparatus for evaluating the electromagnetic conversion characteristic of an MR element in an MR / IND head, wherein M is measured in the X direction and Y direction.
A plane formed by mounting an MR / IND head with the central axis of the MR element oriented in the Z direction of the three-dimensional coordinate system, which is the track width direction and the thickness direction of the R element, and including dispersed electrodes and MR elements connected to the electrodes. A first positioning device having a mounting surface having a dynamic reference mark on the surface, and freely moving in the X, Y and Z directions to position the MR / IND head on the mounting surface; and a variable magnetic field strength. Form a magnetic field with a counter electrode parallel to the reference mark on the lower surface, and the magnetic field direction is Z
A magnetic field applying medium fixed in a direction relative to the MR / IND head, a tester for measuring the electric resistance between the reference mark and the counter electrode, and a surface scanning by a probe to obtain surface irregularity information. And a microscope for combined use of atomic force and magnetic force for obtaining magnetic information, the probe is operated while moving the positioning device to position the MR element, and then the electrical resistance is measured by a tester while moving the positioning device. The positional relationship between the reference mark and the counter electrode is determined, and thereby the probe, the magnetic field direction of the magnetic field applying medium, and the central axis of the MR element are aligned from top to bottom, and then the magnetic field applying medium is positioned. The electromagnetic conversion characteristic of the MR / IND head is measured by changing the magnetic field strength of the MR / IND head.

In a preferred embodiment of the present invention, the magnetic field applying medium is a single magnetic pole head. In another preferred embodiment of the present invention, the magnetic field applying medium is a hard magnetic body having a hard magnetic film formed on a substrate such that the magnetic field strength is different in the X direction, or the magnetic field strength is different. It is characterized in that each of the hard magnetic films is a plurality of sets of hard magnetic materials formed on a substrate.

[0012]

According to the first aspect of the invention, the first positioning device for the MR / IND head and the microscope for both atomic force and magnetic force (hereinafter, simply referred to as AFM / MFM) cooperate with each other to form the MR element and the probe. And the second positioning device for the magnetic field applying medium and the AFM / MFM cooperate with each other to position the magnetic field applying medium with reference to the reference mark.
The positional relationship between the magnetic field applying medium and the probe is obtained. Then, based on the obtained positional relationship, the first and second positioning devices are operated so that the probe, the magnetic field direction of the magnetic field applying medium, and the central axis of the MR element are aligned from top to bottom. MR / I
After positioning the ND head and the magnetic field applying medium, the magnetic field strength of the magnetic field applying medium is changed to measure the electromagnetic conversion characteristics of the MR / IND head. With the above configuration, since the magnetic field applying medium has the magnetic field direction of the Z direction, and the magnetic field direction of the magnetic field applying medium, the center line of the MR element, and the probe are aligned on the same perpendicular line, The MR characteristic can be easily measured.

According to the second aspect of the present invention, the first positioning device for the MR / IND head and the AFM / MFM cooperate with each other to generate M.
The positional relationship between the R element and the probe is obtained, and then the electrical resistance is measured by a tester while moving the positioning device to obtain the positional relationship between the reference mark of the positioning device and the counter electrode of the magnetic field applying medium. MR based on mark
The positional relationship between the element, the probe, and the magnetic field applying medium is established. Then, based on the obtained positional relationship, the positioning device is operated, and from top to bottom, the probe, the magnetic field direction of the magnetic field applying medium,
After positioning so as to match the central axis of the MR element, the magnetic field strength of the magnetic field applying medium is changed to measure the electromagnetic conversion characteristics of the MR / IND head. In the present invention, since the magnetic field applying medium that forms a magnetic field whose magnetic field direction is the Z direction is provided, and the magnetic field direction of the magnetic field applying medium, the center line of the MR element, and the probe are aligned on the same perpendicular line, MR accurately and easily
The property can be measured.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will now be described in more detail based on embodiments with reference to the accompanying drawings. Embodiment 1 FIG. 3 is a conceptual diagram showing the configuration of an embodiment of the invention described in claim 1. The MR characteristic measuring apparatus 10 of the present embodiment is an atomic force and magnetic force microscope (Atomic Force and Magnetic).
Force Microscope (hereinafter abbreviated as AFM / AFM) 12, a magnetic field applying medium 14, a first positioning device 16 for positioning the MR / IND head S, and X, Y and Z directions while holding the magnetic field applying medium 14. Second positioning device 18 for freely moving to position the magnetic field applying medium 14
It has and. The AFM / MFM12 is an atomic force microscope (A that can detect surface irregularity information using atomic force).
FM) and a magnetic probe, which also have the functions of a magnetic force microscope that detects a magnetic distribution by detecting a fine magnetic force, and a cantilever-shaped probe 20 (hereinafter The probe 20 is a known device including only a detection unit at the tip), and is, for example, an AF manufactured by Seiko Denshi Kogyo.
M / MFM etc. can be used.

In the MR characteristic measuring apparatus 10, the X and Y directions of the three-dimensional coordinate system are, as shown in FIG. 1, the track width direction and the thickness direction of the MR element of the MR / IND head S to be measured. Each is set. The first positioning device 16 has a mounting surface 24 parallel to the XY plane on the upper surface thereof, and the MR / IND head S to be measured by aligning the central axis of the MR element F (see FIG. 1) in the Z direction. Mounting surface 24
On the MR / I and move freely in the X, Y and Z directions to
Position the ND head S.

The second positioning device 18 positions the magnetic field applying medium 14 while holding the magnetic field applying medium 14 by the arm 22 in a state where the magnetic field direction is oriented in the Z direction. The magnetic field applying medium 14 is a medium that causes a magnetic field having a variable magnetic field strength to act on the MR element,
It is composed of a single magnetic pole head or a hard magnetic material in which a hard magnetic film is coated on a substrate. Further, on the upper surface of the magnetic field applying medium 14 in the Z direction, a reference mark 26 for positioning having magnetism is provided.
Is provided.

As shown in FIGS. 4A and 4B, the single magnetic pole head 28 has an upper core 30 made of a soft magnetic material.
A magnetic field generating coil 32 for generating a magnetic field, and a substrate 34.
And a magnetic pole 36 made of a soft magnetic material formed on the substrate 34.
It consists of and. At the time of measuring the MR characteristics, the single magnetic pole head 28, as shown in FIGS.
The magnetic pole 36 and the MR element F are positioned with respect to the IND head S so as to be aligned in the same vertical plane, and when a current is passed through the magnetic field generating coil 32, a magnetic field is generated and each is rotated clockwise as indicated by an arrow. Direction and counterclockwise magnetic force lines are emitted to form a magnetic field whose magnetic field direction is the Z direction (direction of arrow). Since the magnetic field strength changes by changing the strength of the current flowing through the magnetic field generating coil 32, the MR element F of the MR / IND head S outputs a signal (voltage) based on the electric resistance according to the acting magnetic field strength. The characteristic curve is as shown in FIG. In the case of the single pole head 28, the upper edge of the pole 34 is used as the reference mark 26. Incidentally, FIG.
Reference numerals C to H in the figure are the same as those described in FIG. 1, and I is a cover.

The hard magnetic material is obtained by forming a hard magnetic film of CoPt or the like on a ceramic substrate made of alumina / titanium / carbite through an insulating film.
As shown in FIGS. 5A and 5B, when the MR element is moved in the X direction, the magnetic field strength is reduced. The hard magnetic body 40 shown in FIG. 5A has a plurality of (in FIG. 5A, five) elongated hard magnetic film bands 44A, B, C, D having the same magnetic field strength on one substrate 42. , E are parallel to each other and arranged at equal intervals in the vertical direction to form a film.
Further, in the hard magnetic body 40, the lower end of the hard magnetic film band 44 coincides with the lower end of the substrate 42 in A, and the distance between the lower end of the hard magnetic film 44 and the substrate 42 becomes an arithmetic series as it goes from B to E. It is formed to be large.

The hard magnetic body 40 shown in FIG. 5B is a hard magnetic film 46 having a different magnetic field intensity for each of the substrates 42A, 42B, 42C.
It is composed of a plurality of sets of hard magnetic materials having different magnetic field strengths, in which A, B, and C are deposited. In addition, magnetic material,
By changing the film thickness or the magnetization direction during magnetization, hard magnetic films having different magnetic field strengths can be formed on each substrate. In the case of the hard magnetic body 40, the upper end portion of the hard magnetic film band 44 shown in FIGS. 5A and 5B functions as the reference mark 26, and as shown in FIG. 6, on the insulating film 48 on the substrate 42. The hard magnetic film 44 is formed, and the thin upper edge portion serves as the reference mark 26. If necessary, the upper end portion of the hard magnetic film 44 can be etched to form a reference mark of any shape.

At the time of measuring the MR characteristics, the hard magnetic body 40 is shown in FIG.
7, the hard magnetic film 44 and the MR element F are arranged so as to be aligned on the same vertical plane with respect to the MR / IND head S, and a magnetic field in the Z direction (direction of the arrow) in FIG. 7 is applied. By moving the hard magnetic body 40 and the MR element shown in FIG. 5A relative to each other in the X direction, the hard magnetic bodies 40 of the set shown in FIG. 5B are used one after another. As a result, the magnetic field strength for the MR element F can be changed.

Next, a method of measuring the MR characteristic of the MR element incorporated in the MR / IND head using the MR characteristic measuring apparatus 10 of the first embodiment will be described. Step 1 As shown in FIG. 3, the MR / IND head S to be measured with the central axis of the MR element F (see FIG. 1) aligned with the Z direction is placed on the mounting surface 24 of the first positioning device 16. AFM /
It moves below the probe 20 of the MFM 12. AFM / MFM
12 in the AFM mode and MR / IN with the probe 20
The surface of the D head, particularly the vicinity of the MR element F, is scanned to detect surface irregularities, and the information is stored in the AFM / MFM 12. Step 2 Next, the AFM / MFM 12 is operated in the MFM mode, and the probe 20 scans the surface of the MR / IND head S.
The position of the MR element of the MR / IND head S is detected, and the position is stored in the AFM / MFM 12. In this scanning, the AFM / MFM 12 runs the probe 20 on the surface of the MR / IND head S so that the distance between the probe 20 and the probe 20 becomes a set value based on the unevenness information detected in step 1. From the operation of the probe 20 that responds only to the magnetic substance, M
The position of the R element is detected, and the positional relationship (XYZ coordinates) between the probe 20 and the MR element is obtained.

Step 3 The first positioning device 16 is operated to position the MR element directly below the probe 20, as shown in FIG. 8, based on the positional relationship between the probe 20 and the MR element obtained in Step 2. To do.
Then, the magnetic field applying medium 1 is interposed between the probe 20 and the MR element F.
4 can be arranged so that the MR element F is moved downward in the Z direction and separated from the probe 20. Step 4 The second positioning device 18 is activated to activate the magnetic field applying medium 14
Is moved below the probe 20. Then steps 1 and 2
Perform the same operation as. That is, AF the AFM / MFM12
When operating in the M mode, the probe 20 scans the upper surface of the magnetic field application medium 14 to detect surface irregularities, and the irregularity information is A
It is stored in the FM / MFM 12. Then, using the AFM / MFM 12 in the MFM mode, the upper surface of the magnetic field applying medium 14 is again scanned to detect the position of the reference mark 26,
Positional relationship between the probe 20 and the reference mark 26 (XYZ coordinates)
Are stored in the AFM / MFM 12.

Step 5 As shown in FIG. 9, the second positioning device 18 is operated to move the reference mark 26 directly below the probe 20 based on the positional relationship between the probe 20 and the reference mark 26 obtained in step 4. To position. As a result, M of the MR / IND head S
The Z direction axis of the R element F and the magnetic field direction of the magnetic field applying medium 14 match. Step 6 The first positioning device 16 or the second positioning device 18 is operated in the Z direction to bring the magnetic field applying medium 14 and the MR / IND head S close to each other.

Step 7 A sense current is passed through the MR element of the MR / IND head, while in the case of the hard magnetic body 40, the hard magnetic body 40 is moved in the X direction. The output voltage of the MR element is measured by flowing a current through the coil while changing the height to form a magnetic field whose magnetic field strength changes. By operating the MR characteristic measuring apparatus 10 of the present embodiment as described above, the magnetic field direction of the magnetic field applying medium 14 and M
Since the center line of the R element F and the probe 20 are aligned on the same vertical line, the MR characteristic can be accurately measured.

Embodiment 2 FIG. 10 (a) is a conceptual diagram showing the construction of an embodiment of the invention described in claim 4. In FIG. MR characteristic measuring apparatus 50 of the present embodiment
As shown in FIG. 10A, the same AF
M / MFM 12, magnetic field applying medium 14, and positioning device 1
8, a support device 54 that is supported by an arm 52 so as to match the magnetic field direction of the magnetic field applying medium 14 with the Z direction and is fixed at a predetermined position, and a counter electrode 6 of the magnetic field applying medium 14 which will be described later.
2, an electrical resistance measuring tester 74 for measuring an electrical resistance with a reference mark 56, which will be described later, is provided. As shown in FIG. 10, the tester 74 is used by being connected to A or B according to the measurement purpose described later. In particular, connect to B and M
When measuring the R characteristic, it functions as a tester having an MR sense current supply source and a voltage output function. As shown in FIG. 10B, the mounting surface 24 of the second positioning device 18 has
A reference mark 56 for positioning, which has a two-dimensional spread, is provided. Further, as shown in FIG. 10C, the lower surface 60 of the magnetic field applying medium 14 is a surface parallel to the XY plane,
A counter electrode 62, which is made of a conductive film, for example, a gold or platinum film, and which faces the reference mark 56, is deposited on the surface. For the magnetic field applying medium 14, the single magnetic pole head 28 or the hard magnetic material 40 is used as in the first embodiment.

The reference mark 56 has a reference point 58 at an arbitrary position within the reference mark 56, and the vertical and horizontal lengths are larger than the vertical and horizontal lengths of the counter electrode 62 on the lower surface 60 of the magnetic field applying medium. Substrate 6 is arranged as shown in FIG.
It is composed of one elongated MR element 66 and a plurality of electrodes 68, 70 and 72 which are formed on the surface of the electrode 4. Electrode 68
Is formed into a plurality of L-shaped patterns that are equally spaced and the long legs are arranged parallel to the MR element 66.
The left end of the short leg is connected to the MR element 66. The electrode 70 has the same width as that of the MR element 66 and is directly formed on the MR element 66. The electrode 72 is M
It is composed of a plurality of elongated electrodes arranged in parallel to the R element 66 and spaced apart at equal intervals. Electrode 68,
The upper surfaces of 70 and 72 are finished parallel to the mounting surface 24 and at the same height. Counter electrode 6 of magnetic field applying medium 14
In FIG. 11, 2 is the length from the right end of 68B to the left end of 72C and the length of 6D from the upper end of 68D in the Y and X directions.
It is equal to the length to the bottom of 8B.

Next, a method of measuring the MR characteristic of the MR element incorporated in the MR / IND head using the MR characteristic measuring apparatus 50 of the second embodiment will be described. Steps 1 and 2 As shown in FIG. 10A, the MR / IND head S to be measured is mounted on the mounting surface 24 of the positioning device 18, and the probe is carried out in the same manner as in Steps 1 and 2 of the first embodiment. 20
And the positional relationship between the MR element and the MR element is obtained. Step 3 Next, the AFM / MFM 12 is used in the AFM mode to scan the reference mark 56 on the mounting surface 24 and detect the position of the reference point 58 of the reference mark 56. From the positional relationship between the probe 20 and the MR element obtained in steps 1 and 2, the positional relationship between the reference point 58 and the MR element and the positional relationship between the electrodes of the reference mark 56 can be known.

Step 4 Next, the positioning device 18 is operated to move the reference mark 56 to a position directly below the magnetic field applying medium 14 as shown in FIG. 12, and the counter electrode of the magnetic field applying medium 14 is set as follows. 6
The reference mark 56 is scanned at 2 to detect the positional relationship between the magnetic field applying medium 14 and the reference mark 56. When a single pole head is used, a current is passed through the magnetic field generating coil 32 (see FIG. 4) to generate a magnetic field. First, the positioning device 18 is moved in the Y direction to move the magnetic field applying medium 14 on the reference mark 56. Then, it is moved in the Z direction to bring the counter electrode 62 of the magnetic field applying medium 14 into contact with the electrode of the reference mark 56, and measure the electric resistance thereof with the electric resistance measuring tester 74. Separate. Next, the positioning device 18 is slightly moved in the Y direction, and the same operation is performed. By repeating this operation, the magnetic field applying medium 1
Position 4 between electrode 72D and electrode 68B. Next, positioning in the X direction is performed. To do so, the positioning device 18 is moved in the X direction, and the MR characteristic between any two terminals in 70 and 68 is measured. At this time, the terminal of the tester 74 is connected to B in FIG. 10, a current of 10 mA or less is passed between any two terminals, and the MR characteristic is measured by measuring the voltage change between the terminals. Then, the magnetic field applying medium 14 is positioned between the electrodes 68B and 68D (YB and YD in FIG. 11). Thereby, the positional relationship between the reference point 58 in the reference mark 56 and the magnetic field applying medium 14 can be known.

Step 5: The positioning device 18 is activated to operate the positional relationship between the reference point 58 obtained in Step 3 and the MR element F of the MR / IND head S and the reference mark 56 obtained in Step 4 and the magnetic field applying medium 14. Based on the positional relationship of
Position on element F (see FIGS. 4 and 7). Step 6 Next, the positioning device 18 is operated to operate the magnetic field applying medium 1
The magnetic field applying medium 14 is lowered and positioned so that the distance between the MR element F and the MR element F becomes a predetermined value. For this purpose, the magnetic field applying medium 14 is once lowered to the extent that it contacts the MR element F,
Then, it is increased in reverse by an interval of a predetermined value. The contact between the magnetic field applying medium 14 and the MR element can be detected by using a resistance measuring tester or the like to check the continuity between the two. Step 7 In the same manner as in Example 1, the MR characteristic is measured. By operating the MR characteristic measuring apparatus 50 of the present embodiment as described above, the magnetic field direction of the magnetic field applying medium 14, the center line of the MR element F, and the probe 20 are aligned on the same perpendicular line. Therefore, the MR characteristic can be accurately measured.

Example 3 The frequency characteristic of the MR / IND head refers to the relationship between frequency (magnetization width) and MR output. Usually, as the frequency becomes higher, the magnetization width becomes shorter and the magnetic field is less likely to enter the MR element. Output of the head decreases. In the present invention, as shown in FIG.
By similarly measuring the MR characteristics by using the single magnetic pole heads 28A and 28B, it is possible to obtain the relationship between the magnitude of the magnetization width, that is, the height of the frequency and the MR output, and evaluate the frequency characteristics. .

Embodiment 4 As shown in FIG. 14, the off-track characteristic can be measured by moving the magnetic field applying medium 14 in the Y direction with respect to the MR element F.

Embodiment 5 By passing a current through the recording coil D of the MR / IND head S and measuring the MR characteristics before and after the current is passed, the stability of the MR characteristics of the MR element can be evaluated.

[0033]

With the above construction, according to the inventions of claims 1 and 4, the magnetic field applying medium forms a magnetic field whose magnetic field direction is the Z direction, and the magnetic field applying medium has a magnetic field direction of M.
Since the center line of the R element and the probe can be easily and precisely aligned on the same perpendicular line, the MR / IND head does not need to be slider-processed and attached to the gimbal plate, which allows accurate and quick electromagnetic conversion. It is possible to measure characteristics such as MR characteristics, frequency characteristics, off-track characteristics, MR element stability, and MR element bias point. Therefore, the MR characteristic measuring device according to the present invention is
Improvement of MR / IND head manufacturing yield and MR / IN
It greatly contributes to the improvement of the characteristics of the D head.

[Brief description of drawings]

FIG. 1 is an exploded perspective view of an MR / IND head.

FIG. 2 is a graph of an MR characteristic curve.

FIG. 3 is a schematic diagram showing the configuration of a first embodiment of the MR characteristic measuring apparatus.

4A and 4B are conceptual longitudinal sectional views showing the relationship between a single pole head and an MR / IND head when measuring MR characteristics.

5 (a) and 5 (b) are conceptual plan views of a hard magnetic material.

FIG. 6 is a top view taken along line I-I of FIG. 5 (a).

FIG. 7 is a conceptual vertical cross-sectional view showing the relationship between a hard magnetic material and an MR / IND head when measuring MR characteristics.

FIG. 8 is a conceptual diagram showing a relationship between a probe and an MR element when measuring MR characteristics.

FIG. 9 is a conceptual diagram showing a relationship among a probe, a magnetic field applying medium, and an MR element when measuring MR characteristics.

10 (a), (b) and (c) are schematic diagrams showing a configuration of a second embodiment of the MR characteristic measuring apparatus, respectively.

11 (a) is an electrode layout diagram of a reference mark, and FIG. 11 (b) is a side view taken along the line II-II of FIG. 11 (a).

FIG. 12 is a schematic diagram for explaining positioning of a magnetic field applying medium and a reference mark.

FIG. 13 is a schematic diagram illustrating a method of detecting frequency characteristics.

FIG. 14 is a schematic diagram illustrating a method of detecting off-track characteristics.

[Explanation of symbols]

 10 First Example of MR Characteristic Measuring Device 12 AFM / AFM 14 Magnetic Field Applying Medium 16 First Positioning Device 18 Second Positioning Device 20 Probe 22 Arm 24 Mounting Surface 26 Reference Mark 28 Single Pole Head 40 Hard Magnetic Material 42 Substrate 44 Hard Magnetic Film 50 Second Example of MR Characteristic Measuring Device 52 Arm 54 Supporting Device 56 Reference Mark 58 Reference Point 62 Counter Electrode 66 MR Element 68, 70, 72 Electrode 74 Tester

Claims (6)

[Claims] 1. An apparatus for evaluating the electromagnetic conversion characteristics of an MR element in an MR / IND head, comprising: a Z in a three-dimensional coordinate system in which the X direction and the Y direction are respectively the track width direction and the thickness direction of the MR element. The MR / IND head is placed with the central axis of the MR element oriented in the X-direction and the Y-direction.
A first positioning device for freely moving and positioning in the Z direction and the Z direction, a magnetic field applying medium having a magnetic reference mark for positioning on the upper end surface and forming a magnetic field with variable magnetic field strength, and a magnetic field direction in the Z direction. Hold the magnetic field in the direction of
A second positioning device that freely moves and positions in the Y-direction, the Y-direction, and the Z-direction, and a microscope for combined use of atomic force and magnetic force that obtains surface irregularity information and magnetic information by scanning the surface with a probe, By operating the probe while moving the first positioning device and the second positioning device based on the reference mark of the magnetic field applying medium,
From top to bottom, the probe, the magnetic field direction of the magnetic field applying medium, and the MR
An MR characteristic measuring apparatus characterized in that the element is positioned so as to coincide with the central axis of the element, and then the magnetic field strength of the magnetic field applying medium is changed to measure the electromagnetic conversion characteristic of the MR element. 2. The MR characteristic measuring apparatus according to claim 1, wherein the magnetic field applying medium is a single magnetic pole head. 3. The magnetic field applying medium is a hard magnetic body having a hard magnetic film formed on a substrate such that the magnetic field strength is different along the X direction, or each of the hard magnetic films having different magnetic field strengths. 2. The MR characteristic measuring apparatus according to claim 1, wherein the MR characteristic measuring apparatus comprises a plurality of sets of hard magnetic materials each formed on a substrate. 4. An apparatus for evaluating the electromagnetic conversion characteristics of an MR element in an MR / IND head, comprising a Z in a three-dimensional coordinate system in which the X direction and the Y direction are the track width direction and the thickness direction of the MR element, respectively. The MR / IND head is placed with the central axis of the MR element oriented in the direction, and a mounting surface having a planar reference mark composed of dispersed electrodes and MR elements connected to the electrodes is provided on the surface, and the X direction, Y direction. A first positioning device that freely moves in the Z direction and the Z direction to position the MR / IND head on the mounting surface; and a counter electrode that forms a magnetic field with variable magnetic field strength and that is parallel to the reference mark on the lower surface. , And a magnetic field applying medium that is fixed relative to the MR / IND head with the magnetic field direction facing the Z direction, a tester that measures the electrical resistance between the reference mark and the counter electrode, and scans the surface with a probe. And then the concave surface It is equipped with a microscope for both atomic force and magnetic force that obtains information and magnetic information. The probe is operated to position the MR element while moving the positioning device, and then the electrical resistance is measured by the tester while moving the positioning device. To obtain the positional relationship between the reference mark and the counter electrode, so that from top to bottom, the probe and
An MR characterized in that the magnetic field direction of the magnetic field applying medium and the central axis of the MR element are positioned so as to coincide with each other, and then the magnetic field strength of the magnetic field applying medium is changed to measure the electromagnetic conversion characteristics of the MR element. Characteristic measuring device. 5. The MR characteristic measuring apparatus according to claim 4, wherein the magnetic field applying medium is a single magnetic pole head. 6. The magnetic field applying medium is a hard magnetic body having a hard magnetic film formed on a substrate so that the magnetic field strength is different along the X direction, or each of the hard magnetic films having different magnetic field strengths. 5. The MR characteristic measuring apparatus according to claim 4, wherein each is a plurality of sets of hard magnetic materials formed on a substrate.