Current-perpendicular-to-plane-GMR (CPP-GMR) heads are expected to be future read sensors beyond 200Gb/in{sup}2. Large noise in metallic CPP-GMR heads is well known theoretically and experimentally to be induced by spin-torque when the sensing current is above the critical magnitude [1, 2]. For CPP-GMR heads with a current screen layer (a nano-oxide layer with confined current paths), the sensing current of the current screen-type is about 1/10 times that of the metallic-type. On the other hand, magnetization switching using a low critical current in a tunneling junction with confined current paths was also reported [3]. Therefore the spin-torque noise might be an important issue for the CPP-GMR heads even with the current screen. In this study, we assessed the head noise of CPP-GMR heads with the current screen layer.
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