Vertical giant magnetoresistive read heads for 50-Gb/in2 magnetic recording

We have designed and fabricated a vertical giant magnetoresistive (VGMR) head for high-density magnetic recording. In this style of recording head, read current flows through the sensor length, which is oriented perpendicular to the air-bearing surface (ABS), and the transducer is fabricated from GMR "sandwich" material. In the VGMR style of head design, the correct bias is obtained through a combination of intrinsic anisotropy, shape anisotropy, and longitudinal bias field generated by the sense current. The material at the edge of the sensor is stabilized using an edge-hardening process, which is designed to prevent switching of the magnetization at the edge of the sensor in a reverse applied field. Both top and bottom shields are recessed away from the ABS in order to increase the signal decay length and boost sensor output. We tested read heads incorporating the VGMR reader design under conditions of up to 50 Gb/in². We describe additional sensor concepts, including folded and differential VGMR head designs.