Magnetic recording head with spin torque oscillator layers satisfying width, thickness and angle relationship formulas

A magnetic recording head comprising:

• a main magnetic pole that generates a recording magnetic field applied on a magnetic recording medium from an end surface that is one portion of an air bearing surface facing the magnetic recording medium;
• a trailing shield provided on the trailing side of the main magnetic pole with a write gap interposed therebetween;
• and
• a spin torque oscillator that is provided in the write gap interposed between the main magnetic pole and the trailing shield, wherein the spin torque oscillator generates a magnetic field that exerts an interaction on the recording magnetic field applied to the magnetic recording medium;
• wherein, among the end surfaces of the main magnetic pole, the end surface positioned on the trailing side is configured by an inclined surface that is inclined toward the trailing side from the air bearing surface toward the back in the height direction;
• the spin torque oscillator is a laminated body in which at least a magnetic field generation layer, a nonmagnetic spacer layer and a spin injection layer are laminated in this order from the main magnetic pole side;
• the length of the write gap in the down-track direction when viewed from the air bearing surface side is 20 nm or less;
• and
• a width WFGL (nm) in the cross-track direction of the end surface facing the main magnetic pole, among the end surfaces of the magnetic field generation layer, a film thickness tFGL (nm) of the magnetic field generation layer, a film thickness tSIL (nm) of the spin injection layer and an angle α (deg) formed by the cross-track direction and a normal line to the end surfaces of the laminated body positioned on both sides in the cross-track direction when viewing the laminated body from the air bearing surface side have relationships indicated by the following formula (1-1) and formula (1-2):
• tanα/WFGL≥−1.72×10−2×(tFGL/tSIL)2+2.95×10−2×tFGL/tSIL+9.60×10−3 (1-1)
• tanα/WFGL≤−3.32×10−5×(tFGL/tSIL)2−2.87×10−3×tFGL/tSIL+4.69×10−2 (1-2).