GIANT MAGNETO-RESISTIVE SENSOR WITH ANTIPARALLEL-COUPLED HIGH RESISTIVITY FREE LAYER

摘要

PURPOSE: A giant magneto-resistive sensor having an AP(anti-parallel)-coupled low anisotropic free layer is provided to reduce the magnetic thickness of the AP-coupled free layer, and to increase the sensitivity with forming the free layer in the spin valve sensor. CONSTITUTION: An AP pinned layer(622) includes first and second ferromagnetic layers(624,628) separated by an APC(anti-parallel coupling) layer(626). An AP coupled free layer(632) includes a third ferromagnetic layer(633) to a spacer layer, a fourth ferromagnetic layer(637) due to the high temperature stability for generating the mirror surface reflection of electron. An APC layer(635) is held between third and fourth ferromagnetic layers(634,636). Lowering of sensing current is reduced by the free layer. The giant magneto-resistive coefficient of the spin valve sensor is improved by reduction of sensing current lowering and the mirror surface reflection of electron.