IP Library › Granted Patent US 7,088,548
Granted Patent B2
US 7,088,548 · App. 10/677,302 · Granted Aug 8, 2006

Perpendicular magnetic recording system

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Quick Facts
Patent No.
US 7,088,548
App. No.
10/677,302
Granted
Aug 8, 2006
Kind
B2
Abstract

To make a soft magnetic underlayer of a double layered perpendicular magnetic recording medium thinner than heretofore while avoiding saturation. Assuming that T b1 is the thickness of the soft magnetic underlayer of the double layered perpendicular magnetic recording medium, B S2 the saturation flux density of the same, T m the thickness of a magnetic recording head's main pole 1 along a track direction in the vicinity of its floating surface, T WW the track width of the same, and B S1 the saturation flux density of the same, then T b1 <(B S1 ×T m ×T WW )/2(B S2 ×(T m +T WW )) is satisfied.

Claims (14)

1. A perpendicular magnetic recording system comprising:

a perpendicular magnetic recording medium having a soft magnetic underlayer and

a magnetic head having a magnetic recording head and a magnetic read head,

wherein said magnetic read head comprises an upper shield, a lower shield and a read element provided between said upper shield and said lower shield,

wherein said magnetic recording head comprises a main pole for recording a magnetization reversal on said perpendicular magnetic recording medium,

the perpendicular magnetic recording system satisfying

T b1 <( B s1 ×T m ×T ww )/2( B s2 ×( T m +T ww )),

wherein T b1 is the thickness of said soft magnetic underlayer, B s2 is the saturation flux density of the same, T m is the thickness of said main pole along a track direction in the vicinity of its floating surface, T ww is the track width of the same, B s1 is the saturation flux density of the same, and T ww is less than 0.5 μm.

2. The perpendicular magnetic recording system according to claim 1 , wherein said magnetic recording head further comprises an auxiliary pole.

3. The perpendicular magnetic recording system according to claim 2 , wherein said auxiliary pole is said upper shield.

4. The perpendicular magnetic recording system according to claim 1 , wherein a distance between said main pole and said auxiliary pole is greater than or equal to 0.5 μm.

5. The perpendicular magnetic recording system according to claim 1 , wherein T b1 is smaller than or equal to 0.2 μm.

6. The perpendicular magnetic recording system according to claim 1 , wherein the thickness T b1 of said soft magnetic underlayer satisfies

T b1 >0.25( B si ×T m ×T ww )/2( B S2 ×( T m +T ww )).