Advanced Cpp-Gmr Spin-Valve Sensors For Narrow Reader Applications

The near-future ultra-high-density magnetic recording with an assist recording technology requires a substantial evolution of the read-head technology. A read sensor with a small sensor resistance-area product (RA), a large magnetoresistance ratio (Delta R/R), and a thin total sensor thickness is required for the low bit error rate and high-spatial resolution of reading. We developed currentperpendicular- to-plane giant magnetoresistance sensors using highly spin-polarized Heusler alloy ferromagnetic layers with the spin polarization of the conducting electron beta similar to 0.8. A reasonably large Delta R/R up to 14% was obtained by a practical bottom-pinned spin-valve structure with a conventional metallic spacer layer of an Ag90Sn10 (AgSn) alloy. By replacing the spacer layer with a conductive oxide-based AgSn/InZnO bilayer, a large Delta R/R up to 32% was realized at RA value of similar to 0.1 Omega . mu m(2), which is optimal for the read sensor application. A large voltage output up to 6 mV was obtained for a sensor utilization of similar to 33% at a bias voltage of 100 mV.