Magnetic head for perpendicular magnetic recording including two side shields configured to enable a reduction in width of an end face of the main pole located in a medium facing surface and an increase in cross-sectional area of the main pole in the vicinity of the medium facing surface

A magnetic head for perpendicular magnetic recording, comprising:

• a medium facing surface configured to face a recording medium;
• a coil configured to produce a magnetic field corresponding to data to be written on the recording medium;
• a main pole configured to pass a magnetic flux corresponding to the magnetic field produced by the coil, and to produce a write magnetic field for writing the data on the recording medium by means of a perpendicular magnetic recording system;
• a write shield formed of a magnetic material;
• a gap section formed of a nonmagnetic material and provided between the main pole and the write shield;
• and
• a substrate having a top surface, wherein
• the coil, the main pole, the write shield and the gap section are disposed above the top surface of the substrate,
• the write shield includes a first side shield and a second side shield located on opposite sides of the main pole in a track width direction,
• the first side shield has a first end face located in the medium facing surface, and has a first sidewall and a second sidewall facing the main pole,
• the second side shield has a second end face located in the medium facing surface, and has a third sidewall and a fourth sidewall facing the main pole,
• the first sidewall is connected to the first end face,
• the second sidewall is located farther from the medium facing surface than is the first sidewall,
• the third sidewall is connected to the second end face,
• the fourth sidewall is located farther from the medium facing surface than is the third sidewall,
• the first sidewall has a first edge farthest from the top surface of the substrate,
• the second sidewall has a second edge farthest from the top surface of the substrate,
• the third sidewall has a third edge farthest from the top surface of the substrate,
• the fourth sidewall has a fourth edge farthest from the top surface of the substrate,
• each of the first and third edges has a front end located in the medium facing surface and a rear end opposite to the front end,
• each of the second and fourth edges has a front end closest to the medium facing surface,
• a distance between the rear end of the first edge and the rear end of the third edge in the track width direction is greater than a distance between the front end of the first edge and the front end of the third edge in the track width direction,
• a distance between the second edge and the fourth edge in the track width direction increases with increasing distance from the medium facing surface,
• the first edge and the second edge are contiguous to each other to form a first contour line, the rear end of the first edge and the front end of the second edge coinciding with each other,
• the third edge and the fourth edge are contiguous to each other to form a second contour line, the rear end of the third edge and the front end of the fourth edge coinciding with each other,
• the front end of the second edge is an inflection point or a corner at which there occurs a change in an angle of inclination of the first contour line relative to a first direction at a first point on the first contour line when the first point is shifted from the first edge to the second edge, the first direction being perpendicular to the medium facing surface, the change being a decrease,
• the front end of the fourth edge is an inflection point or a corner at which there occurs a change in an angle of inclination of the second contour line relative to the first direction at a second point on the second contour line when the second point is shifted from the third edge to the fourth edge, the change being a decrease,
• the main pole has an end face located in the medium facing surface, and has a first side surface and a second side surface,
• part of the first side surface is opposed to the first sidewall,
• part of the second side surface is opposed to the third sidewall,
• the gap section includes a first portion interposed between the first side surface and the first and second sidewalls, and a second portion interposed between the second side surface and the third and fourth sidewalls,
• a distance from the medium facing surface to the front end of the second edge, and a distance from the medium facing surface to the front end of the fourth edge are each within a range of 20 to 90 nm, and
• a distance between the front end and the rear end of the first edge in the track width direction, and a distance between the front end and the rear end of the third edge in the track width direction are each within a range of 40 to 290 nm.