US 12,451,156 B2
Dual-spin torque oscillator designs in microwave assisted magnetic recording
Wenyu Chen, San Jose, CA (US); Zhenyao Tang, Chiba (JP); Shohei Kawasaki, Sunnyvale, CA (US); and Tetsuya Roppongi, San Jose, CA (US)
Assigned to Headway Technologies, Inc., Milpitas, CA (US)
Filed by Headway Technologies, Inc., Milpitas, CA (US)
Filed on Jul. 25, 2022, as Appl. No. 17/872,831.
Prior Publication US 2024/0029759 A1, Jan. 25, 2024
Int. Cl. G11B 5/11 (2006.01); G11B 5/187 (2006.01); G11B 5/00 (2006.01)
CPC G11B 5/11 (2013.01) [G11B 5/187 (2013.01); G11B 2005/0024 (2013.01)] 15 Claims
OG exemplary drawing
 
1. A spin transfer torque assisted write head comprising:
a main pole configured to obtain a current flow and generate a first magnetic field to interact with a magnetic recording medium;
a trailing shield; and
a spin torque device disposed in a write gap portion between the main pole and the trailing shield, the spin torque device comprising at least two spin torque oscillators (STOs), wherein a spin sink is disposed between each of the at least two STOs, wherein each STO includes:
a non-magnetic spin sink adjacent to themain pole that includes a spin diffusion length less than a thickness of the non-magnetic spin sink;
a first magnetic field generation layer (FGL) layer;
a first magnetic spin injection layer (SIL) layer between the non-magnetic spin sink and the first FGL layer;
a second SIL layer,
a second FGL layer disposed between the first FGL layer and the second SIL layer;
a first non-magnetic spacer disposed between the first FGL layer and the first SIL layer; and
a second non-magnetic spacer disposed between the second FGL layer and the second SIL layer, wherein the first non-magnetic spacer includes a spin diffusion length greater than a thickness of the first non-magnetic spacer, wherein the first FGL layer and the second FGL layer oscillate in a same frequency and oscillate out of phase with one another, wherein mutual spin transfer torques are configured to be enabled between adjacent layers in the spin torque device, and wherein the first FGL layer and the second FGL layer are configured to be driven into an angle oscillation as a result of the mutual spin transfer torques, with the angle oscillation forming a second magnetic field to assist in writing at the main pole.