Dynamic magnetic information storage or retrieval – Head – Core
Patent
1998-02-20
2000-08-15
Evans, Jefferson
Dynamic magnetic information storage or retrieval
Head
Core
360113, G11B 531, G11B 539
Patent
active
061045748
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to a high-speed transfer, large-capacity magnetic recording method associated with a high-frequency recording operation, and in particular, to a narrow-track magnetic head and a magnetic memory apparatus using the head operating in accordance with the recording method.
BACKGROUND ART
An example in which a magnetic head is combined with a conductive film to improve performance of the head by use of an eddy current flowing through the conductive film has been described, for example, in "Minimization of Inductance of Head by Magnetic Shielding Effect" written in page 115 of the "17th Japan Applied Magnetic Engineering Society Proceedings". In the prior art, a surface of a ferrite head core for a VTR is covered with a non-magnetic conductive film. A magnetic flux which will leak through the film to an outside space of the head core is confined in the head core by the magnetic shielding effect due to an eddy current loss. This reduces the head inductance and hence improves efficiency of the core. In this example, surfaces of a coil and a core of the VTR ferrite head are covered with copper films to improve the head efficiency.
Additionally, an example in which an end portion of an upper magnetic pole has a reversely tapered contour when viewed from a side of a sliding surface has been described in "Dual Stripe Magnetoresistive Heads for High Density Recording" written in pages 303 to 308 of the "IEEE Transactions On Magnetics", Vol. 30, No. 2, March 1994. Since the recording head of the conventional example includes head poles manufactured through a plating procedure, the end portions are formed with a surface having a reversely tapered contour rather than an exactly vertical contour. However, peripherals of magnetic poles are sandwiched with regions of an insulating alumina protective layer.
FIG. 9 shows a conventional example related to the present invention. FIG. 9 includes an insulative layer (non-conductive film) 14.
It is an object of the present invention to provide a narrow-track magnetic head and a magnetic memory apparatus using a recording head in which magnetic saturation in the end portion of the pole due to minimization of track width of the recording head is prevented to thereby enable a narrow-track recording on a medium having a high coercive force and which implements a high-speed transfer, large-capacity magnetic recording method associated with a high-frequency recording operation with reduced write blur.
DISCLOSURE OF INVENTION
The object above is achieved by a magnetic head having features described below and a magnetic memory apparatus using the head.
A first feature of the present invention resides in (1) a magnetic head and a magnetic memory apparatus using the head in which at least a portion of poles constructing a magnetic path through a recording gap is sandwiched between conductive materials with respect to a track width direction.
In (1) above, it is favorable (2) that the conductive material has resistivity less than that of a material of the magnetic pole constituting the magnetic path. This is because the leakage magnetic field is canceled by the eddy current loss.
In (1) above, it is favorable (3) that the conductive material has resistivity equal to or less than 20 .mu..OMEGA.-cm. This is because the write blur is minimized (reference is to be made to FIG. 4).
In (1) above, it is favorable (4) that those magnetic poles not sandwiched between the conductive materials among the plural magnetic poles forming the magnetic path of the head includes a step in a track width direction. This is because the write blur can be further minimized.
A second feature of the present invention resides in (5) a magnetic head and a magnetic memory apparatus using the head in which at least a portion of the plural magnetic poles configuring a magnetic path through a recording gap is sandwiched between conductive materials with respect to the track width direction and in which an expression Tww'.gtoreq.Tww is satisfied, where Tww is the width of
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Aihara Makoto
Fuyama Moriaki
Kawabe Takashi
Maruyama Yohji
Takano Hisashi
Evans Jefferson
Hitachi , Ltd.
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