Patent ID: 10699731

Abstract:
A perpendicular magnetic recording writer is disclosed with a permanent magnet (PM) formed within a write gap (WG) that is between a main pole (MP) trailing side and a trailing shield. The PM has a magnetization that is anti-parallel to a WG field (HWG) when a transition is written thereby enhancing the MP field on a magnetic bit, and generates a PM field that assists the MP field. When HWG becomes saturated after the transition is written and exceeds PM coercivity that is from 500 Oe to 8000 Oe, PM magnetization flips to an opposite direction and reduces the MP field thereby improving adjacent track erasure. The PM may be at the air bearing surface (ABS) or recessed up to 50 nm from the ABS, and has a down-track thickness less than the WG thickness, and a cross-track width≤to the track width of the MP trailing side.