Perpendicular magnetic recording write head and system with improved spin torque oscillator for microwave-assisted magnetic recording

A magnetic recording disk drive perpendicular recording write head for magnetizing regions in data tracks of a perpendicular magnetic recording layer on the disk, the head being formed on a slider having an air-bearing surface (ABS) lying substantially in a plane parallel to the X-Z plane of an X-Y-Z coordinate system and comprising:

• a substrate;
• a write pole on the substrate and aligned generally parallel to the Y-axis, the write pole having an end substantially at the ABS;
• an electrically conductive coil coupled to the write pole, the write pole generating a magnetic write field in the presence of electrical write current through the coil;
• a trailing shield on the substrate and formed of magnetically permeable material for altering the angle of the write field, the trailing shield being spaced from the write pole along the Z-axis;
• a spin torque oscillator (STO) on the substrate between the write pole and the trailing shield and comprising a stack of layers with planes generally parallel with the X-Y plane, said stack including a ferromagnetic polarizer layer having a magnetization, in the presence of the write field from the write pole, oriented at an angle φp between 20 degrees and 80 degrees from the Z-axis, a free ferromagnetic layer having a magnetization oriented at a non-zero angle ψ to the Z-axis and free to rotate about the Z-axis in the presence of electrical current through the free layer, and a nonmagnetic electrically conductive spacer between the polarizer layer and the free layer;
• and
• circuitry coupled to the STO and capable of supplying direct current through the stack when write current is supplied to the coil.