Sensor shape of a CPP magnetic head for improving the MR ratio
Embodiments of the present invention help to prevent a head characteristic from being deteriorated by re-deposition or damage which occurs when a sensor film is etched, a track width is narrowed, and the head characteristic is stabilized. According to one embodiment, when it is assumed that the thickness of the sensor film on an air bearing surface is T, and a distance between an end of a medium layer that is interposed between a free layer and a pinned layer which comprise the sensor film and an end of the sensor film lowest portion, a relationship of 1.2×T≦X≦2.5×T is satisfied, and the ends of a pair of magnetic films which are in contact with both sides in the track-width direction through an insulator do not exist in the track central portion from the free layer end. The sensor film is etched while an incident angle of an etching beam is changed over, and when it is assumed that a direction normal to the sensor film surface is the incident angle of 0, etching is conducted under the condition where the incident angle of the etching beam becomes smaller with time.
1. A thin film magnetic head, comprising:
a sensor film comprising a free layer, a pinned layer, and a medium layer disposed between the free and pinned layers; and
an upper shield disposed above a top layer of the sensor film; and
a lower shield disposed below a bottom layer of the sensor film, wherein the upper and lower shields allow a current to flow through the sensor film in a thickness direction extending between the bottom and top layers,
wherein a relationship of 1.2×T≦X is satisfied, wherein T is a thickness of the sensor film as measured in the thickness direction, and wherein X is a distance, in a track-width direction that is perpendicular to the thickness direction, between an end of the medium layer at a side surface of the sensor film and an end of the bottom layer at the side surface of the sensor film.
2. The thin film magnetic head according to claim 1 , wherein X≦2.5×T is satisfied.
3. The thin film magnetic head according to claim 1 , wherein the sensor film has a skirt air bearing surface configuration such that at least a portion of the side surface of the sensor film is curved.
4. The thin film magnetic head according to claim 3 , wherein an air bearing surface of the lower shield intersects with the curved portion of the side surface such that the air bearing surface extends the curvature defined by the curved portion of the side surface.
5. The thin film magnetic head according to claim 1 , wherein the sensor film has a skirt air bearing surface such that a first portion of the skirt air bearing surface between the medium layer and the top layer has a dimension that is substantially constant in the track-width direction, and wherein a second portion of the skirt air bearing surface between the medium layer and the bottom layer has a curved side such that the dimension of the second portion increases as the curved side approaches the bottom layer.
6. The thin film magnetic head according to claim 1 , further comprising a pair of magnetic films respectively disposed on two sides of the sensor film in the track-width direction, wherein one of the pair of magnetic films is disposed in the track-width direction from an end of the free layer at the side surface.
7. The thin film magnetic head according to claim 1 , wherein the bottom layer directly contacts the lower shield.
8. The thin film magnetic head according to claim 7 , wherein the bottom layer is closer to the pinned layer than to the free layer.
9. The thin film magnetic head according to claim 1 , wherein the bottom layer is closer to the pinned layer than to the free layer.
10. A thin film magnetic head, comprising:
a sensor film comprising a free layer, a pinned layer, and a medium layer disposed between the free and pinned layers;
an upper shield disposed above a top layer of the sensor film; and
a lower shield disposed below a bottom layer of the sensor film, wherein the upper and lower shields allow a current to flow through the sensor film in a thickness direction extending between the bottom and top layers,
wherein a relationship of 1.2×T≦X≦2.5×T is satisfied, wherein T is a thickness of the sensor film as measured in the thickness direction, and wherein X is a distance, in a track-width direction that is perpendicular to the thickness direction, between an end of the medium layer at a side surface of the sensor film and an end of the bottom layer at the side surface of the sensor film,
wherein the sensor film has a skirt air bearing surface such that a first portion of the skirt air bearing surface between the medium layer and the top layer has a dimension that is substantially constant in the track-width direction, and wherein a second portion of the skirt air bearing surface between the medium layer and the bottom layer has a curved side such that the dimension of the second portion increases as the curved side approaches the bottom layer, and
wherein an air bearing surface of the lower shield intersects with the curved side of the bottom layer such that the air bearing surface extends a curvature defined by the curved side.
11. The thin film magnetic head according to claim 10 , further comprising a pair of magnetic films respectively disposed on two sides of the sensor film in the track-width direction, wherein one of the magnetic films is disposed in the track-width direction from an end of the free layer at the side surface.
12. The thin film magnetic head according to claim 11 , wherein the bottom layer is closer to the pinned layer than to the free layer.
13. The thin film magnetic head according to claim 10 , wherein the bottom layer directly contacts the lower shield.