Magnetic head, head gimbal assembly with the same, and disk drive

Abstract

According to one embodiment, a magnetic head includes a main pole configured to apply a recording magnetic field to a recording layer of a recording medium, a return pole opposed to the main pole with a write gap therebetween, and a high-frequency oscillator between respective facing surfaces of the main pole and the return pole and configured to produce a high-frequency magnetic field. At least one of the main and return poles faces the high-frequency oscillator and includes a laminated structure portion includes a magnetic layer and a nonmagnetic layer laminated to one another.

1 . A magnetic head comprising:
 a main pole configured to apply a recording magnetic field to a recording layer of a recording medium;   a return pole opposed to the main pole with a write gap therebetween; and   a high-frequency oscillator between respective facing surfaces of the main pole and the return pole and configured to produce a high-frequency magnetic field,   at least one of the main and return poles facing the high-frequency oscillator and comprising a laminated structure portion comprising a magnetic layer and a nonmagnetic layer laminated to one another.   
     
     
         2 . The magnetic head of  claim 1 , wherein the high-frequency oscillator comprises a first magnetic layer and a second magnetic layer arranged between the main pole and the return pole, the coercivity of the first magnetic layer being lower than that of a magnetic field applied from the main pole, and the coercivity of the second magnetic layer being lower than that of the magnetic field applied from the main pole. 
     
     
         3 . The magnetic head of  claim 2 , further comprising a current source configured to supply current to the high-frequency oscillator through the return pole and the main pole, wherein the return pole comprises a junction spaced apart from the write gap and connected to the main pole through an insulator or a semiconductor. 
     
     
         4 . The magnetic head of  claim 1 , wherein the oscillation frequency f (Hz) of the high-frequency oscillator, saturation magnetization Ms (emu/cc) of the magnetic layers, and film thickness t (cm) of each of the magnetic layers are related as follows: 
       
         
           
             
               
                 
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         5 . The magnetic head of  claim 1 , wherein the material of the nonmagnetic layers contains at least one of elements including ruthenium, tungsten, copper, rhenium, gold, silver, tantalum, aluminum, and magnesium. 
     
     
         6 . The magnetic head of  claim 1 , wherein the film thickness of each of the nonmagnetic layers ranges from 0.2 to 1 nm. 
     
     
         7 . The magnetic head of  claim 1 , wherein the main pole comprises a projection projecting toward the high-frequency oscillator, the projection constituting the laminated structure portion. 
     
     
         8 . The magnetic head of  claim 1 , wherein the main pole and the return pole each comprises the laminated structure portion. 
     
     
         9 . The magnetic head of  claim 1 , wherein the laminated structure portion constitutes the entire main pole. 
     
     
         10 . The magnetic head of  claim 1 , wherein the magnetic layers and the nonmagnetic layers are alternately laminated along the width of the write gap at the laminated structure portion. 
     
     
         11 . The magnetic head of  claim 1 , wherein the magnetic layers and the nonmagnetic layers are alternately laminated along the height of the write gap at the laminated structure portion. 
     
     
         12 . A head gimbal assembly comprising:
 a slider;   the magnetic head of  claim 1  on the slider; and   a suspension configured to support the slider.   
     
     
         13 . A disk drive comprising:
 a disk recording medium comprising a recording layer having a magnetic anisotropy perpendicular to a surface of the medium;   a drive unit configured to support and rotate the recording medium; and   the magnetic head of  claim 1  which processes data on the recording medium.