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DOUBLE DUAL HEAD WITH ONLY ONE AFM

IP.com Disclosure Number: IPCOM000013734D
Original Publication Date: 2000-Apr-01
Included in the Prior Art Database: 2003-Jun-18

Publishing Venue

IBM

Abstract

A cross-section of the double dual head is shown in Figure 1. This design uses two FREE layers to enhance the GMR coefficient of the sensor through enhanced spin dependent scattering. The key feature is that the design accomplishes double dual function only with one antiferromagnetic layer in the middle of the structure. The outer pinned layers are pinned by the field from the current. The thicknesses of the outer pinned layers are selected so that FM(1) and FM(9) are thicker than the neighbouring ferromagnetic layers. The current flows out of the plane of the paper. The field from the current then pins the FM(1) magnetization away from the air bearing surface and the magnetization of FM(9) layer into the air bearing surface. This arrangement then provides in-phase magnetizations for the pinned layers around the two FREE layers. The arrangement therefore provides addition of the read signal from the two FREE layers leading to enhancement of output signal. The use of single antiferromagnetic layer provides thinner total stack of the GMR sensor for future short read gap heads. Figure 1 1