Thin-film magnetic head, head gimbal assembly, and hard disk system

Abstract

A write shield layer that forms a part of a thin-film magnetic head is set with respect to the widthwise full length W thereof lying substantially on an air bearing surface that is opposite to the recording medium such that when the full length W is trisected, the maximum thickness H 1/3side thereof in a range of widthwise ⅓W size positioned at both ends thereof is larger than the average thickness H m of the whole write shield layer from the air bearing surface up to the rear (H 1/3side >H m ), so that the so-called external magnetic field resistance is improved, and inadvertent erasure of the information already recorded in the recording medium is avoided as much as possible. Besides, the PTP (pole tip protrusion) phenomenon arising from the generation of heat from coils, and external temperature changes can be held back.

1 . A thin-film magnetic head comprising a recording head portion adapted to record magnetic information in a recording medium, wherein: 
 said recording head portion comprises:    a thin-film coil adapted to generate a magnetic flux,    a magnetic pole layer, which extends from a surface toward the rear, wherein said surface is opposite to the recording medium moving in a medium traveling direction, and which is adapted to generate a magnetic field for magnetizing said recording medium in a direction orthogonal to a surface thereof on the basis of the magnetic flux generated at said thin-film coil, and    a write shield layer, which is located on a side of said magnetic pole layer in said medium traveling direction, and extends from said surface opposite to the recording medium toward the rear, whereby said write shield layer is isolated by a gap layer from said magnetic pole layer on a side near to said surface opposite to the recording medium and joined through a back gap to said magnetic pole layer on a side far away from said surface opposite to the recording medium, wherein:    said write shield layer is set with respect to a widthwise full length W lying substantially on an air bearing surface that is opposite to the recording medium such that when said full length W is trisected, a maximum thickness H 1/3side  thereof in a range of widthwise ⅓W size positioned at both ends thereof is larger than an average thickness H m  of the whole write shield layer from the air bearing surface up to the rear (H 1/3side >H m ).    
   
   
       2 . A thin-film magnetic head as recited in  claim 1 , wherein said magnetic pole layer has a multilayer structure comprising a main magnetic pole layer that extends from the surface toward the rear, wherein said surface is opposite to the recording medium moving in the medium traveling direction, and is adapted to generate a magnetic field for magnetizing said recording medium in a direction orthogonal to a surface thereof on the basis of the magnetic flux generated at said thin-film coil, and an auxiliar magnetic pole layer that extends from a first position toward the rear, wherein said first position is retracted from said surface opposite to the recording medium on said traveling direction side, wherein said main magnetic pole layer and said auxiliar magnetic pole layer are stacked together.  
   
   
       3 . A thin-film magnetic head as recited in  claim 1 , wherein said write shield layer comprises a first magnetic shield portion that extends from said surface opposite to the recording medium to a second position in front of said first position while being adjacent to said gap layer, and a second magnetic shield portion that extends from said surface opposite to the recording medium to at least said back gap while resting partially on said first magnetic shield portion.  
   
   
       4 . A thin-film magnetic head as recited in  claim 1 , wherein a bottom spacer layer is previously formed in such a way as to put up both ends of said write shield layer near the air bearing surface.  
   
   
       5 . A thin-film magnetic head as recited in  claim 1 , wherein bottom spacer layer pieces made of the same material as the thin-film coil are previously spotted such that upon formation of the thin-film coil for generating a magnetic flux, both ends near of the air bearing surface of the write shield layer to be formed later can be put up, and an insulating film is thereafter formed and the write shield layer is formed on said insulating film.  
   
   
       6 . A thin-film magnetic head as recited in  claim 1 , wherein a bottom spacer layer is previously formed in such a way as to put up both ends of said write shield layer near the air bearing surface, and an insulating film and the write shield layer are successively formed on the bottom spacer layer.  
   
   
       7 . A thin-film magnetic head as recited in  claim 1 , wherein bottom spacer layer pieces made of the same material as the thin-film coil are previously spotted such that upon formation of the thin-film coil for generating a magnetic flux, both ends near of the air bearing surface of the write shield layer to be formed later can be put up, and an insulating film is thereafter formed, and the write shield layer is formed on said insulating film, so that the write shield layer is formed directly on the bottom space layer pieces.  
   
   
       8 . A thin-film magnetic head as recited in  claim 1 , wherein bottom spacer layer pieces functioning as a bottom spacer layer and made of the same material as the thin-film coil are previously spotted such that upon formation of the thin-film coil for generating a magnetic flux and formation of an insulating film in such a way as to cover said thin-film coil, both ends near of the air bearing surface of the write shield layer to be formed later can be put up, and the write shield layer is formed on said insulating film.  
   
   
       9 . A thin-film magnetic head as recited in  claim 1 , wherein an insulating film is determined in terms of form and location such that upon formation of the thin-film coil for generating a magnetic flux and formation of the insulating film in such a way as to cover said thin-film coil, both ends near of the air bearing surface of the write shield layer to be formed later can be put up, and the write shield layer is formed on said insulating film.  
   
   
       10 . A thin-film magnetic head as recited in  claim 1 , wherein insulating film pieces functioning as a bottom spacer layer and made of the same material as an insulating film are previously spotted such that upon formation of the thin-film coil for generating a magnetic flux and formation of the insulating film in such a way as to cover said thin-film coil, both ends near of the air bearing surface of the write shield layer to be formed later can be put up, and the write shield layer is formed on said insulating film, wherein an upper portion of said write shield layer is flattened.  
   
   
       11 . A thin-film magnetic head comprising a reproducing head portion adapted to reproduce magnetic information recorded in a recording medium, wherein: 
 said reproducing head portion comprises a magneto-resistive effect device, and an upper read shield layer and a lower read shield layer which are located above and below said device to isolate said device magnetically from the surroundings, wherein:    said upper read shield layer and said lower read shield layer extend from a surface toward the rear, wherein said surface is opposite to the recording medium moving in a medium traveling direction, and    said upper read shield layer is set with respect to a widthwise full length Wup thereof lying substantially on an air bearing surface that is the surface opposite to the recording medium such that when the full length Wup is trisected, an average thickness Hup 1/3side  thereof in a range of widthwise ⅓Wup size positioned at both ends thereof is larger than an average thickness Hup m  of the whole upper read shield layer from the air bearing surface up to the rear (Hup 1/3side >Hup m ).    
   
   
       12 . A thin-film magnetic head comprising a reproducing head portion adapted to reproduce magnetic information recorded in a recording medium, wherein: 
 said reproducing head portion comprises a magneto-resistive effect device, and an upper read shield layer and a lower read shield layer which are located above and below said device to isolate said device magnetically from the surroundings, wherein:    said upper read shield layer and said lower read shield layer extend from a surface toward the rear, wherein said surface is opposite to the recording medium moving in a medium traveling direction, and    said lower read shield layer is set with respect to a widthwise full length Wdn thereof lying substantially on an air bearing surface that is the surface opposite to the recording medium such that when the full length Wdn is trisected, an average thickness Hdn 1/3side  thereof in a range of widthwise ⅓Wdn size positioned at both ends thereof is larger than an average thickness Hdn m  of the whole lower read shield layer from the air bearing surface up to the rear (Hdn 1/3side >Hdn m ).    
   
   
       13 . A thin-film magnetic head comprising a reproducing head portion adapted to reproduce magnetic information recorded in a recording medium, wherein: 
 said reproducing head portion comprises a magneto-resistive effect device, and an upper read shield layer and a lower read shield layer which are located above and below said device to isolate said device magnetically from the surroundings, wherein:    said upper read shield layer and said lower read shield layer extend from a surface toward the rear, wherein said surface is opposite to the recording medium moving in a medium traveling direction,    said upper read shield layer is set with respect to a widthwise full length Wup thereof lying substantially on an air bearing surface that is the surface opposite to the recording medium such that when the full length Wup is trisected, an average thickness Hup 1/3side  thereof in a range of widthwise ⅓Wup size positioned at both ends thereof is larger than an average thickness Hup m  of the whole upper read shield layer from the air bearing surface up to the rear: (Hup 1/3side >Hup m ), and    said lower read shield layer is set with respect to a widthwise full length Wdn thereof lying substantially on an air bearing surface that is the surface opposite to the recording medium such that when the full length Wdn is trisected, an average thickness Hdn 1/3side  thereof in a range of widthwise ⅓Wdn size positioned at both ends thereof is larger than an average thickness Hdn m  of the whole lower read shield layer from the air bearing surface up to the rear (Hdn 1/3side >Hdn m ).    
   
   
       14 . A head gimbal assembly comprising a slider including a thin-film magnetic head and located in such a way as to be opposite to a recording medium, and a suspension adapted to resiliently support said slider, wherein: 
 said thin-film magnetic head comprises a recording head portion adapted to record magnetic information in the recording medium, wherein:    said recording head portion comprises:    a thin-film coil adapted to generate a magnetic flux,    a magnetic pole layer, which extends from a surface toward the rear, wherein said surface is opposite to the recording medium moving in a medium traveling direction, and which is adapted to generate a magnetic field for magnetizing said recording medium in a direction orthogonal to a surface thereof on the basis of the magnetic flux generated at said thin-film coil, and    a write shield layer, which is located on a side of said magnetic pole layer in said medium traveling direction, and extends from said surface opposite to the recording medium toward the rear, whereby said write shield layer is isolated by a gap layer from said magnetic pole layer on a side near to said surface opposite to the recording medium and joined through a back gap to said magnetic pole layer on a side far away from said surface opposite to the recording medium, wherein:    said write shield layer is set with respect to a widthwise full length W lying substantially on an air bearing surface that is opposite to the recording medium such that when said full length W is trisected, a maximum thickness H 1/3side  thereof in a range of widthwise ⅓W size positioned at both ends thereof is larger than an average thickness H m  of the whole write shield layer from the air bearing surface up to the rear (H 1/3side >H m ).    
   
   
       15 . A head gimbal assembly comprising a slider including a thin-film magnetic head and located in such a way as to be opposite to a recording medium, and a suspension adapted to resiliently support said slider, wherein: 
 said thin-film magnetic head comprises a reproducing head portion adapted to reproduce magnetic information recorded in the recording medium, wherein:    said reproducing head portion comprises a magneto-resistive effect device, and an upper read shield layer and a lower read shield layer which are located above and below said device to isolate said device magnetically from the surroundings, wherein:    said upper read shield layer and said lower read shield layer extend from a surface toward the rear, wherein said surface is opposite to the recording medium moving in a medium traveling direction,    said upper read shield layer is set with respect to a widthwise full length Wup thereof lying substantially on an air bearing surface that is the surface opposite to the recording medium such that when the full length Wup is trisected, an average thickness Hup 1/3side  thereof in a range of widthwise ⅓Wup size positioned at both ends thereof is larger than an average thickness Hup m  of the whole upper read shield layer from the air bearing surface up to the rear (Hup 1/3side >Hup m ).    
   
   
       16 . A hard disk system comprising a slider including a thin-film magnetic head and located in such a way as to be opposite to a rotationally driven disk-form recording medium, and a positioning device adapted to support said slider and position said slider with respect to said recording medium, wherein: 
 said thin-film magnetic head comprises a recording head portion adapted to record magnetic information in the recording medium, wherein:    said recording head portion comprises:    a thin-film coil adapted to generate a magnetic flux,    a magnetic pole layer, which extends from a surface toward the rear, wherein said surface is opposite to the recording medium moving in a medium traveling direction, and which is adapted to generate a magnetic field for magnetizing said recording medium in a direction orthogonal to a surface thereof on the basis of the magnetic flux generated at said thin-film coil, and    a write shield layer, which is located on a side of said magnetic pole layer in said medium traveling direction, and extends from said surface opposite to the recording medium toward the rear, whereby said write shield layer is isolated by a gap layer from said magnetic pole layer on a side near to said surface opposite to the recording medium and joined through a back gap to said magnetic pole layer on a side far away from said surface opposite to the recording medium, wherein:    said write shield layer is set with respect to a widthwise full length W lying substantially on an air bearing surface that is opposite to the recording medium such that when said full length W is trisected, a maximum thickness H 1/3side  thereof in a range of widthwise ⅓W size positioned at both ends thereof is larger than an average thickness H m  of the whole write shield layer from the air bearing surface up to the rear (H 1/3side >H m ).    
   
   
       17 . A hard disk system comprising a slider including a thin-film magnetic head and located in such a way as to be opposite to a rotationally driven disk-form recording medium, and a positioning device adapted to support said slider and position said slider with respect to said recording medium, wherein: 
 said thin-film magnetic head comprises a reproducing head portion adapted to reproduce magnetic information recorded in the recording medium, wherein:    said reproducing head portion comprises a magneto-resistive effect device, and an upper read shield layer and a lower read shield layer which are located above and below said device to isolate said device magnetically from the surroundings, wherein:    said upper read shield layer and said lower read shield layer extend from a surface toward the rear, wherein said surface is opposite to the recording medium moving in a medium traveling direction, and    said upper read shield layer is set with respect to a widthwise full length Wup thereof lying substantially on an air bearing surface that is the surface opposite to the recording medium such that when the full length Wup is trisected, an average thickness Hup 1/3side  thereof in a range of widthwise ⅓Wup size positioned at both ends thereof is larger than an average thickness Hup m  of the whole upper read shield layer from the air bearing surface up to the rear (Hup 1/3side >Hup m ).