Patent ID: 7532433

Claim:
A magnetic disk drive including a magnetic recording medium, a perpendicular magnetic recording head, and a positioning device for positioning the perpendicular magnetic recording head over the magnetic recording medium, said magnetic disk drive supplying write electrical current to the perpendicular magnetic recording head, said perpendicular magnetic recording head comprising: a main pole including a magnetic multilayer composed of a high saturation flux density layer and a low saturation flux density layer, a return path for supplying a magnetic flux to the main pole, and a conductive coil for excitation of the return path, wherein: the high saturation flux density layer contains an Fe—Co alloy, the width of the main pole is 200 nanometers or less, and the direction of magnetization in a pair of the high saturation flux density layers of the magnetic multilayer facing each other with respect to the low saturation flux density layer is oriented in an antiparallel arrangement by magnetostatic coupling between magnetization of the high saturation flux density layers.