Magnetic head for perpendicular recording and magnetic disk storage apparatus mounting the head

Abstract

A magnetic head is composed to diminish disordered writing bits of a recording layer or reading noise caused by a magnetic field generated from an under layer without decreasing a writing magnetic field strength of the magnetic head. The magnetic head includes a write head provided with a main pole and one or more auxiliary poles, a read head provided with a read element, and coils located on both sides of the main pole in a manner to sandwich the main pole. The coil located on one side generates the asymmetrical magneto-motive force for magnetizing the main pole to that generated by the coil located on the other side.

What is claimed is:  
     
         1 . A magnetic head comprising: 
 a main pole;    one or more auxiliary poles; and    coils each composed of a looped thin-film conductor coil, said coils being located on both sides of said main pole in a manner to sandwich said main pole; and    wherein said coil located on one side generates different magneto-motive force from that of said coil located on the other side.    
     
     
         2 . A magnetic head as claimed in  claim 1 , wherein said auxiliary pole is located only on one side of said main pole so that the magneto-motive force of said coil located on the side having no auxiliary pole may be greater than that of said coil located on the side having said auxiliary pole.  
     
     
         3 . A magnetic head as claimed in  claim 1 , wherein the ratio of the magneto-motive forces of said coils located on respective sides is 1.5 or more.  
     
     
         4 . A magnetic head as claimed in  claim 1 , wherein the ratio of the magneto-motive forces of said coils located on respective sides is 2.5 or less.  
     
     
         5 . A magnetic head as claimed in  claim 1 , wherein said auxiliary pole is located only on one side of said main pole so that a value of current applied into said coil located on the side having no auxiliary pole may be greater than a value of current applied into said coil located on the side having said auxiliary pole.  
     
     
         6 . A magnetic head as claimed in  claim 5 , wherein a ratio of applied current values of said coils located on respective sides is 1.5 or more.  
     
     
         7 . A magnetic head as claimed in  claim 5 , wherein a ratio of applied current values of said coils located on respective sides is 2.5 or less.  
     
     
         8 . A magnetic head as claimed in  claim 1 , wherein said auxiliary pole is located only on one side of said main pole and the number of windings of said coil located on the side having no auxiliary pole is greater than that of said coil located on the side having said auxiliary pole.  
     
     
         9 . A magnetic head as claimed in  claim 8 , wherein a ratio of the number of windings of said coils located on respective sides is 1.5 or more.  
     
     
         10 . A magnetic head as claimed in  claim 8 , wherein a ratio of the number of windings of said coils located on respective sides is 2.5 or less.  
     
     
         11 . A magnetic head comprising: 
 a main pole;    one or more auxiliary poles; and    coils each composed of a looped thin-film conductor coil, said coils being located on both sides of said main pole in a manner to sandwich said main pole; and    wherein said coil located on one side is caused to generate magneto-motive force for magnetizing said main pole that is asymmetrical to that generated by said coil located on the other side.    
     
     
         12 . A magnetic head as claimed in  claim 1 , wherein a distance between said main pole and said auxiliary pole is twice or less as long as the thickness of each coil located between said main pole and said auxiliary pole.  
     
     
         13 . A magnetic head comprising: 
 a read and write composite head having;    said magnetic head claimed in  claim 1  being served as a read head, and    a read head composed of a read element and two shield films located in a manner to sandwich said read element.    
     
     
         14 . A magnetic head as claimed in  claim 13 , wherein an auxiliary pole that is one of the components of said read head is formed integrally with and uses one of said shield films composing said read head.  
     
     
         15 . A magnetic head as claimed in  claim 13 , wherein said read head is located on the opposite side to said auxiliary pole in a manner to sandwich said main pole.  
     
     
         16 . A magnetic head as claimed in  claim 15 , wherein a distance between said main pole and said auxiliary pole is smaller than a distance between said main pole and said shield film closer to said main pole.  
     
     
         17 . A magnetic head comprising: 
 a main pole;    auxiliary poles;    coils; and    said auxiliary poles and said coils being located on a trailing side and a leading side in a manner to sandwich said main pole, the opposed area of one auxiliary pole to a floating surface being made smaller than the opposed area of the other auxiliary pole to said floating surface, and the magneto-motive force of said coil located on the side of said auxiliary pole with a smaller area being made greater than that of said coil located on the side of said auxiliary pole with a larger area.    
     
     
         18 . A magnetic head as claimed in  claim 17 , wherein the current applied to said coil located on said auxiliary pole with a smaller area is greater than the current applied to said coil located on said auxiliary pole with a larger area.  
     
     
         19 . A magnetic head as claimed in  claim 17 , wherein the number of windings located on said auxiliary pole with a smaller area is greater than that located on said auxiliary pole with a larger area.  
     
     
         20 . A magnetic head comprising: 
 a read and write composite head having;    a magnetic head described in  claim 17  being served as a write head;    a read head composed of a read element and two shield films located in a manner to sandwich said read element; and    said read head being located on the side of said auxiliary pole with a smaller area.