At two sides of a multilayer film including a free magnetic layer, a first
non-magnetic material layer, and a fixed magnetic layer, extension
portions extending from the fixed magnetic layer are formed. At lower
sides of the extension portions, a pair of first antiferromagnetic layers
is formed with a space therebetween in a track width direction, and in
addition, at upper sides of the extension portions, a pair of second
antiferromagnetic layers is formed with a space therebetween in the track
width direction.