PILE SPIN-TORQUE OSCILLATOR WITH AF-MODE OSCILLATION FOR GENERATING HIGH AC-FIELD IN MICROWAVE-ASSISTED MAGNETIC RECORDING

The present disclosure generally relates to a structure for a perpendicular microwave-assisted magnetic recording head used in a magnetic disk drive. A first spin-torque oscillator and a second spin-torque oscillator are positioned between the main pole of a recording head and a trailing shield, and are separated by a spin torque shield layer. The first spin-torque oscillator comprises a first magnetic layer, a first non-magnetic interlayer, and a second magnetic layer. The second spin-torque oscillator comprises a third magnetic layer, a second non-magnetic interlayer, and a fourth magnetic layer. An applied current is adapted to flow in a direction from the second magnetic layer to the first magnetic layer, and from the fourth magnetic layer to the third magnetic layer.