Side shielded magnetoresistive (MR) read head with perpendicular magnetic free layer

摘要

A MR sensor is disclosed that has a free layer (FL) with perpendicular magnetic anisotropy (PMA) which eliminates the need for an adjacent hard bias structure to stabilize free layer magnetization and minimizes shield-FL interactions. In a TMR embodiment, a seed layer, free layer, junction layer, reference layer, and pinning layer are sequentially formed on a bottom shield. After patterning, a conformal insulation layer is formed along the sensor sidewall. Thereafter, a top shield is formed on the insulation layer and includes side shields that are separated from the FL by a narrow read gap. The sensor is scalable to widths <50 nm when PMA is greater than the FL self-demag field. Effective bias field is rather insensitive to sensor aspect ratio which makes tall stripe and narrow width sensors a viable approach for high RA TMR configurations. Sensor sidewalls may extend into the seed layer or bottom shield.

主权项

1. A magneto-resistive (MR) sensor, comprising:
(a) a bottom shield having a top surface; (b) a patterned sensor stack of layers including a seed layer, magnetic free layer, junction layer, magnetic reference layer, and an exchange pinning layer that are sequentially formed on a pedestal portion of the bottom shield top surface, the pedestal portion has a side that extends below a bottom surface of the seed layer, and said free layer has a magnetization and magnetic anisotropy formed perpendicular to the top surface of the bottom shield in a zero field environment, and parallel to the bottom shield top surface when a magnetic field is applied in an in-plane direction, the reference layer has a magnetization parallel to the bottom shield top surface wherein the reference layer's magnetization direction is maintained by exchange coupling from the exchange pinning layer, and each of the layers in the sensor stack adjoins an air bearing surface (ABS); (c) an insulation layer adjoining the side of the pedestal portion and formed on a portion of the bottom shield top surface adjacent to the pedestal portion; and (d) a top shield contacting a top surface of the patterned sensor stack such that there is electrical contact between the top and bottom shields, said top shield includes side shield sections formed on and adjoining the insulation layer, the side shield sections have a bottom surface formed below a top surface of the pedestal portion of the bottom shield.