Magnetic heads for perpendicular recording and magnetic recording disk apparatus using the same

1. A magnetic head comprising:

at least a main pole;

wherein a profile of the main pole on a magnetic head air bearing surface is such that it is composed of a first portion whose length in a cross-track direction continuously increases from a leading edge to a trailing edge, and a second portion located on a side of the trailing edge of the first portion, and the second portion has a length in the cross-track direction at the trailing edge which is substantially equal to a length in the cross-track direction at the point of contact between the first and second portions;

wherein a rate of change in the length of the second portion in the cross-track direction from a leading edge to the trailing edge is different from the rate of increase in the length of the first portion in the cross-track direction; and

wherein the length of the second portion in a track running direction is smaller than the length of the first portion in the track running direction.

2. The magnetic head as claimed in claim 1 , wherein a first magnetic film has a first position inside the main pole where a length in the cross-track direction is larger than a length in the cross-track direction on the magnetic head air bearing surface; a second magnetic film has a second position inside the main pole where a length in the cross-track direction is larger than a length in the cross-track direction on the magnetic head air bearing surface; the first position and the second position with respect to the air bearing surface are different; and taking a distance between the first position and a first magnetic film air bearing surface edge as Ly1 and a distance between the second position and a second magnetic film air bearing surface edge as Ly2, a relation of Ly2>Ly1 is satisfied.

3. A magnetic recording disk apparatus having at least a magnetic head incorporating a main pole, a magnetic disk medium, and means for rotating the magnetic disk medium in a fixed direction;

wherein a the profile of the main pole on a magnetic head air bearing surface is such that it is composed of a first portion whose length in the cross-track direction continuously increases from a upstream side to a downstream side in a rotational direction of the magnetic disk, and a second portion located on the downstream side of the first portion in the disk rotational direction;

wherein a length of the second portion in the cross-track direction at a downstream edge thereof in the magnetic disk rotational direction is substantially equal to a length thereof in the cross-track direction at a point of contact between the first and second portions;

wherein a rate of change in the length of the second portion in the cross-track direction from the upstream side to the down stream side in the rotational direction of the magnetic disk medium is different from a rate of change in the length of the first portion in the cross-track direction from the upstream side to the downstream side in the rotational direction of the magnetic disk medium; and

wherein the length of the second portion in a track running direction is smaller than the length of the first portion in the track running direction.

4. The magnetic head as claimed in claim 3 , wherein a first magnetic film has a first position inside the main pole where a length in the cross-track direction is larger than a length in the cross-track direction on the magnetic head air bearing surface; a second magnetic film has a second position inside the main pole where a length in the cross-track direction is larger than a length in the cross-track direction on the magnetic head air bearing surface; the first position and the second position with respect to the air bearing surface are different; and taking a distance between the first position and a first magnetic film air bearing surface edge as Ly1 and a distance between the second position and a second magnetic film air bearing surface edge as Ly2, a relation of Ly2>Ly1 is satisfied.