Magnetic head for perpendicular recording and magnetic disk storage apparatus mounting the head
View Patent ↗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.
1. A magnetic head comprising:
a reproducing head having an upper shield, a lower shield, and a reproducing element disposed between said upper shield and said lower shield;
a recording head having a main magnetic pole, a first auxiliary magnetic pole, a second auxiliary magnetic pole, and a first excitation coil and a second excitation coil disposed at both sides of said main magnetic pole, said first excitation coil is formed between said main magnetic pole and said first auxiliary magnetic pole, said second excitation coil is formed between said main magnetic pole and said second auxiliary magnetic pole;
wherein an area opposed to a floating surface side of said first auxiliary magnetic pole and an area opposed to a floating surface side of said second auxiliary magnetic pole are asymmetric, a number of turns of coil of said first excitation coil and a number of turns of coil of said second excitation coil are asymmetric, said main magnetic pole is excited by applying current to pass said first excitation coil and said second excitation coil, and a magnetomotive force of said first excitation coil and a magneto-motive force of said second excitation coil are asymmetric.
2. A magnetic head comprising:
a main magnetic pole;
a first auxiliary magnetic pole;
a second auxiliary magnetic pole having an area opposed to a floating surface that is larger than that of said first auxiliary magnetic pole;
a first excitation coil and a second excitation coil formed at both sides of said main magnetic pole;
said first excitation coil is formed between said main magnetic pole and said first auxiliary magnetic pole,
said second excitation coil is formed between said main magnetic pole and said second auxiliary magnetic pole;
a number of turns of said first excitation coil is larger than that of said second excitation coil;
said main magnetic pole is excited by applying current to pass said first excitation coil and said second excitation coil; and
a magneto-motive force of said first excitation coil is larger than that of said second excitation coil.
3. A magnetic head according to claim 2 , wherein a magneto-motive force of said first excitation coil is smaller than four times that of said second excitation coil.
4. A magnetic head according to claim 2 , wherein a ratio of a number of turns of coil between said first and second excitation coils is more than or equal to 1.5.
5. A magnetic head according to claim 2 , wherein a ratio of number of turns of said first and second excitation coils is less than or equal to 2.5.
6. A magnetic head according to claim 2 , wherein a magneto-motive force of said first excitation coil and second excitation coil are asymmetric.
7. A magnetic head according to claim 2 , wherein current values applied to said first excitation coil and said second excitation coil are approximately constant.