Analysis of Effective Field Gradient in Microwave-Assisted Magnetic Recording

Microwave-assisted magnetic recording (MAMR) is one of the promising techniques for future high recording density hard disk drives. In this paper, we estimate the effective field gradient in MAMR using the relation between recorded transition length πa and field gradient by dynamic write process simulation. The effective field gradients reach 600 and 700 Oe/nm on each optimum field generation layer (FGL)-position and FGL oscillation frequency when the microwave field strength (c - H_ac) are 700 and 950 Oe, respectively. These results indicate extremely high linear density would be possible by MAMR.