Patent ID: 7911737

Claim:
A perpendicular magnetic recording (PMR) head comprising: a metal underlayer, the metal underlayer being amorphous; a PMR pole on the metal underlayer, the PMR pole having a top and a bottom, the top being wider than the bottom, the PMR pole including at least a first ferromagnetic layer, a second ferromagnetic layer, and a third ferromagnetic layer, the first ferromagnetic layer being antiferromagnetically coupled with the second ferromagnetic layer, the second ferromagnetic layer being antiferromagnetically coupled with the third ferromagnetic layer, wherein the PMR pole further includes a first nonmagnetic layer and a second nonmagnetic layer, the first nonmagnetic layer residing between the first ferromagnetic layer and the second ferromagnetic layer, the second nonmagnetic layer residing between the second ferromagnetic layer and the third ferromagnetic layer, the first nonmagnetic layer having a first thickness such that the first ferromagnetic layer and the second ferromagnetic layer are antiferromagnetically coupled, the second nonmagnetic layer having a second thickness such that the second ferromagnetic layer and the third ferromagnetic layer are antiferromagnetically coupled; and wherein the first magnetic layer has a first magnetization, the second magnetic layer has a second magnetization, and the third magnetic layer has a third magnetization, the second magnetic layer being substantially a sum of the first magnetization and the third magnetization.