We investigated the feasibility of a spin-dependent tunneling ͑SDT͒ read head with a parallel hard bias. In this scheme, the longitudinal biasing to the free layer is provided by fringe fields from a hard magnet which is fabricated over or under the free layer. A linear response to the applied field is achieved for a SDT junction biased with 400 Å CoCrPt underneath. Thinner CoCrPt layers yield Barkhausen jumps in the free layer. Micromagnetic simulation indicates the bias field at the edge of the free layer is smaller than that which would result from an abutted magnet. The simulation results are similar to experimental data, and indicate that shielded devices with 400 Å permanent magnet will provide stable transfer curves.
The physical properties of spin valve films grown on the surface of nano-oxide layers were studied as a function of Cu spacer layer thickness. In comparison to identical structures without the oxide surface, the films exhibited an increase in ΔR/R of 30% accompanied by a reduction of only 5% in resistance. Semiclassical calculations were preformed on these films with a close match to experiment. Assuming the oxide layer did not cause drastic changes in the properties of the other film layers, the specular reflection was changed to obtain a match with experiment. The increase in giant magnetoresistance response was achieved by increasing the specular reflection at the metal/oxide interfaces from 15% to 85%, indicating high efficiency for specular reflection at the nano-oxide interface.
High saturation magnetization soft magnetic materials are required for future high-density recording heads as well as high frequency inductors. In this work, (Fe 0.7 Co 0.3 ) 1-x
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