JP2509073Y2 - Magnetic head - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a magnetic head, and more particularly to a magnetic head used in an R-DAT device or the like for improving a gap structure to realize high density recording.

2. Description of the Related Art With the realization of high-density recording in recent years, a metal medium has been used as the magnetic recording medium for recording and reproducing information on a magnetic recording medium. On the other hand, as a magnetic head used for such high density recording, MIG (Metal in Gap)
There is a head.

For example, a conventional structure example of the MIG head used in the R-DAT device will be described with reference to FIGS. Fifth
In the MIG head (1) shown in FIGS. 7 to 7, (2)
Is a bulk core chip made of ferrite, which is a ferromagnetic material, and a pair of cores (2a) and (2b) are connected to glass (3) (4).
It is joined and integrated in (4). A magnetic gap g having a predetermined track width t is formed on the magnetic recording medium of the core chip (2), that is, on the top end surface (5) of the core chip (2) which is slidably in contact with the magnetic medium.
Is protected by glass (4) (4). (6) and (6) are metal layers deposited on the edge portions (2a ') and (2b') of the cores (2a) and (2b) located in the magnetic gap g and are formed on the cores (2a) and (2b). A metal ferromagnetic material having a high saturation magnetic flux density characteristic such as sendust, permalloy or amorphous is deposited on the end surfaces of the edge portions (2a ') (2b') by vapor deposition or sputtering. (7) is wound around the cores (2a) and (2b) by a predetermined number of turns by using the winding locking grooves (8a) and (8b) of the cores (2a) and (2b) and the winding insertion hole (9). It is a copper wire rod.

Since the MIG head (1) is provided with the high saturation magnetic flux density metal layers (6) and (6) as described above, information at a high recording density using the magnetic medium (10) having a high coercive force characteristic is provided. Recording and reproduction of are realized.

Problems to be Solved by the Invention By the way, in the above-mentioned MIG head (1), the adhesion between the metal layers (6) and (6) and the cores (2a) and (2b) in the magnetic gap g is low. When the metal layers (6) and (6) are formed, the portions of the metal layers (6) and (6) near the interfaces with the cores (2a) and (2b) are magnetically deteriorated and easily become non-magnetic. As a result, the pseudo gap g ′ in which the interface between the cores (2a) (2b) and the metal layers (6) (6) is parallel to the magnetic gap g,
g '. With such pseudo gaps g'and g ', when reproducing the information written in the magnetic medium (10) by the MIG head (1), the output waveform (A) as shown in FIG. Occurs. The output reproduction waveform (A) by the MIG head (1) undesirably causes rises (n) and (n) due to the pseudo gaps g'and g'on both sides of the rise (m) due to the magnetic gap g. However, due to the rising (n) and (n), there is a problem that accurate reproduction is difficult and error operation frequently occurs.

In order to solve this problem, there are TSS type MIG heads (11) and (12) shown in FIG. 9 and an X type shown in FIG. 9 and 10 show the MIG head (11) (1
It is a partial top view which shows the top end faces (13) and (14) of 2). As shown in the figure, this TSS type and X type MIG head (11)
(12) is a thin metal layer (15) (1) with respect to the magnetic gap g.
6) is provided along the diagonal direction. In addition, (17) and (18) in the figure are glasses that protect the magnetic gap g from both sides. In the MIG heads (11) and (12), recording tracks (T) (T) of a magnetic medium (not shown) slidingly contacting the top end surfaces (13) and (14) of the MIG heads in the direction orthogonal to the magnetic gap g. ), The pseudo gaps g ″ and g ″ are arranged to be inclined. Therefore, both heads (11) (1
In 2), in the output waveform (A) at the time of reproduction shown in FIG. 8, the rising (n) due to the pseudo gaps g ″ and g ″ occurring on both sides of the rising (m) due to the magnetic gap g.
Since (n) is misaligned over the track width t of the magnetic gap g, the rising (m ') due to the magnetic gap g (broken line in FIG. 8) becomes gentle, and the error operation hardly occurs. And accurate reproduction can be realized.

However, in the above-mentioned TSS-type and X-type MIG heads (11) and (12), the thickness of the metal layers (15) and (16) must be increased to about 30 μm due to their manufacturing, and the magnetic gap Since the track width t of g depends on the polishing amount of the joint surface of the core, it is difficult to perform the polishing with high accuracy, and as a result, it is very difficult to set the track width t to a desired value. Met. Further above MIG head (11)
(12) is a metal layer (15) on the top end faces (13) (14)
Since the shape of (16) is complicated, there is a problem that the number of manufacturing steps increases.

Therefore, an object of the present invention is to provide a MIG head which is easy to manufacture and has an improved pseudo gap function.

Means for Solving the Problems The present invention has been proposed in view of the above problems, and a magnetic gap is formed on the top end face of a core chip in which a pair of cores made of ferrite are joined and integrated. A MIG head that achieves the above-mentioned object by providing a metal layer made of a ferromagnetic material having a high saturation magnetic flux density at the edge portion, and setting the thickness of the metal layer to 1/2 or less of the shortest recording bit length. Is.

Effect According to the present invention, since the thickness of the metal layer of the magnetic gap is set to 1/2 or less of the shortest recording bit length, the rise due to the pseudo gap is absorbed within the rise due to the magnetic gap in the output waveform characteristics during reproduction. , It is possible to suppress the generation of an error signal due to the above pseudo gap and enable accurate reproduction.

Embodiment An embodiment of the magnetic head according to the present invention is shown in FIGS.
This will be described with reference to the drawings. In addition, MI of FIG. 5 to FIG.
The same parts as those of the G head (1) are designated by the same reference numerals, and the description thereof will be omitted. The feature of the MIG head (20) of the present invention lies in the metal layers (21) (21). This metal layer (21) (21)
Is the edge part (2a ') of the magnetic gap (2a) (2b)
On the (2b ') end face, a metal ferromagnet having a high saturation magnetic flux density such as sendust, permalloy or amorphous is thinly deposited and formed by vapor deposition or sputtering. The film thickness d of the metal layers (21) and (21) is set to 1/2 or less of the shortest recording bit length (l) of the magnetic recording medium, for example, the magnetic medium (10). In the magnetic medium (10), the slower the relative moving speed of the head, the shorter the recording bit length (l). That is, 1 / of the recording bit length (l) on the recording track of the magnetic medium (10)
The film thickness d of the metal layers (21) and (21) may be set to 2 or less. This shortest recording bit length (l) is the same as the above head (20).
It is determined by the relative moving speed of the magnetic recording medium (10) and the recording frequency.

In the MIG head (20) of the present invention, similar to the MIG head (1) shown in FIG. 5, pseudo gaps g ′, g ′ parallel to the magnetic gap g are formed, but more than the MIG head (1) described above. The pseudo gaps g ′ and g ′ are arranged close to the magnetic gap g under the above-mentioned conditions. As a result, when reproducing information,
The output waveform (B) as shown in FIG. 4 is obtained. In this output waveform (B), since the pseudo gaps g ′ and g ′ are arranged close to the magnetic gap g, the rise (n) (due to the pseudo gaps g ′ and g ′ within the rise (m) of the magnetic gap g. n) is included, and the rising (n) (n) due to the pseudo gaps g ′ and g ′ that cause the error operation is eliminated.

As described above, the reason why the error signal due to the pseudo gap can be suppressed is that if the metal layer film thickness is 1/2 or less of the shortest recording bit length, the reversal reduction in the minute section of the magnetic field in the rising magnetic medium due to the pseudo gap is caused. It is thought that this is because the recording demagnetization loss action caused causes the cancellation.

Further, the MIG head (20) is easier to manufacture than the TSS type and X type MIG heads (11) and (12) shown in FIGS. 9 and 10, and the metal layers (21) and (21) are It is easy to reduce the film thickness.

In the above embodiments, the metal tape is described as the magnetic recording medium, but the present invention is not limited to this, and it is of course applicable to other high density recording media such as magnetic disks. 3.5 inch magnetic disk (1
0) is rotated at a rotation speed of 300 rpm, if the recording frequency is 125 KHZ, the shortest recording bit length (l) is 2.9.
Since the thickness is μm, the film thickness d of the metal layers (21) and (21) is 2.9 / 2.
Set to less than μm. When the recording frequency is 625 MHz, the shortest recording bit length (l) is 0.58 μm, and therefore the film thickness d of the metal layers (21) and (21) may be set to 0.58 / 2 μm or less.

Effect of the Invention According to the present invention, the thickness of the metal layer is set to the shortest recording bit length.
Since it is 1/2 or less, the error operation due to the pseudo gap formed at the interface between the metal layer and the core can be reduced,
It is possible to provide a highly reliable magnetic head having a simple structure that realizes accurate information reproduction.

[Brief description of drawings]

1 to 4 are for explaining one embodiment of the present invention. FIG. 1 is a perspective view showing a MIG head, FIG. 2 is a plan view of FIG. 1, and FIG. FIG. 4 is an enlarged sectional view of an essential part showing a portion near the magnetic gap of the figure head, and FIG. 4 is a characteristic diagram showing an output waveform of the head of FIG. FIG. 5 is a perspective view showing an example of a conventional MIG head, FIG. 6 is a plan view of FIG. 5, and FIG. 7 is an enlarged sectional view of an essential part showing a portion near a magnetic gap of the head of FIG. FIG. 5 is a characteristic diagram showing the output waveform of the head, and FIGS. 9 and 10 are enlarged partial plan views showing the top end faces of the TSS type and X type MIG heads. (2a) (2b) ... core, (2a ') (2b') ... edge part, (5) ... top face, (20) ... magnetic head [MIG head], (21) ... metal layer , G ... Magnetic gap, d ...
... film thickness, l ... shortest recording bit length

Claims (1)

(57) [Scope of utility model registration request] 1. A magnetic gap is formed on the top end surface of a core chip in which a pair of cores made of ferrite are joined and integrated.
A metal layer made of a ferromagnetic material having a high saturation magnetic flux density is provided at the edge portion of the magnetic gap, and the film thickness of the metal layer is set to 1/2 or less of the shortest recording bit length. Magnetic head.