Microwave-assisted magnetic recording (mamr) write head with compensation for dc shunting field

A microwave-assisted magnetic recording (MAMR) write head for magnetizing regions of a magnetic recording layer, the head comprising:

• a write pole;
• a trailing shield;
• an electrically conductive coil coupled to the write pole and capable of generating a magnetic write field between the write pole and the trailing shield;
• electrical circuitry coupled to the write pole and the trailing shield and capable of generating electron flow from the trailing shield to the write pole;
• a spin torque oscillator (STO) between the write pole and the trailing shield, the STO comprising a ferromagnetic field generation layer (FGL) having a magnetization, a ferromagnetic spin-polarizing layer (SPL) having a magnetization, and a first nonmagnetic spacer layer between the FGL and the SPL, the FGL being located between the write pole and the SPL and adapted to have its magnetization substantially in the direction of the write field in the presence of a write field and electron flow, the SPL being adapted to have its magnetization flip to be substantially opposite the direction of magnetization of the FGL in the presence of electron flow and a write field;
• a ferromagnetic compensation layer between the write pole and the FGL;
• a nonmagnetic barrier layer between the compensation layer and the FGL;
• a second nonmagnetic spacer layer between the write pole and the compensation layer;
• wherein the FGL is adapted to have its magnetization precess in the presence of electron flow to thereby provide microwave-assisted magnetic recording to the recording layer, the precessing FGL magnetization generating a DC shunting field that opposes the write field;
• and
• wherein the compensation layer is adapted to have its magnetization flip to be substantially opposite the direction of FGL magnetization in the presence of electron flow to thereby generate a DC compensation field for offsetting said DC shunting field in the presence of electron flow.

A microwave-assisted magnetic recording (MAMR) disk drive perpendicular recording write head for magnetizing regions in data tracks of a perpendicular magnetic recording layer on a disk, the head being formed on a slider having a gas-bearing surface (GBS) and comprising:

• a substrate;
• a write pole on the substrate and having an end substantially at the GBS;
• a nonmagnetic spacer layer on the write pole;
• a ferromagnetic compensation layer on the spacer layer and having a magnetization and an edge substantially at the GBS;
• a nonmagnetic barrier layer on the compensation layer;
• a spin torque oscillator (STO) comprising a ferromagnetic free layer on the barrier layer and having a magnetization and an edge substantially at the GBS, a ferromagnetic spin-polarizing layer (SPL), and a nonmagnetic STO spacer layer between the free layer and the SPL;
• a nonmagnetic capping layer on the SPL;
• a trailing shield on the capping layer;
• STO electrical circuitry coupled to the STO capable of generating electron flow from the trailing shield to the write pole;
• and
• an electrically conductive coil coupled to the write pole capable of generating a magnetic write field between the write pole and the trailing shield;
• wherein the free layer is adapted to have its magnetization oriented substantially parallel to the write field in the presence of a write field, the free layer generating a DC shunting field that opposes the write field in the presence of STO electron flow;
• and
• wherein the compensation layer is adapted to have its magnetization flip to be substantially antiparallel to the magnetization of the free layer in the presence of electron flow, the compensation layer generating a compensation field for offsetting said DC shunting field in the presence of electron flow.