Thin film magnetic head, head gimbals assembly, head arm assembly, and magnetic disk unit with improved air bearing surface

A thin film magnetic head, comprising:

• a magnetic pole including an end surface exposed on an air bearing surface;
• and
• a heating element including a first branch and a second branch and configured to heat a vicinity of the magnetic pole, the first branch and the second branch each expanding along a stacking surface and being coupled in parallel to each other, and the stacking surface intersecting the air bearing surface, wherein
• the first branch includes a first extending part extending in a track width direction that is parallel to both the air bearing surface and the stacking surface,
• the second branch includes a second extending part extending in the track width direction,
• the first extending part and the second extending part are adjacent to each other with a distance in between in a height direction orthogonal to the air bearing surface,
• the first extending part has a first width in the height direction,
• the second extending part has a second width in the height direction, the second width being different from the first width,
• the heating element includes a first coupling part and a second coupling part, the first coupling part coupling one end of the first branch to one end of the second branch, and the second coupling part coupling the other end of the first branch to the other end of the second branch, and
• a first length of a first path from the first coupling part to the second coupling part of the first branch is different from a second length of a second path from the first coupling part to the second coupling part of the second branch.