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B 3 Microscopic Origins of Enhanced Output of Heusler Alloy Cpp-gmr Readers by Amorphous Underlayer and Conductive Oxide Spacer
| Content Provider | Semantic Scholar |
|---|---|
| Author | Nakatani, Tomoya Li, Shuangyu Sakuraba, Yuya Sasaki, Taisuke T. Tajiri, Hiroo |
| Copyright Year | 2017 |
| Abstract | As the read sensor size is decreased, the sensor resistance increases and the electrical noise increases. Therefore, reducing the resistance-area product (RA) of sensor film is the central issue for realizing the read sensors for ultrahigh recording density HDDs. All-metallic current-perpendicular-to-plane giant magnetoresistance (CPP-GMR) using highly spin-polarized Co-based Heusler alloys have demonstrated large CPP-GMR ratio over 40% at low RA < 0.05 Ω μm2 [1, 2]. This was achieved by annealing single-crystalline Heusler alloy films at high temperature above 500 °C to obtain a high degree of L21 or B2 chemical order of Heusler alloys. For the realization of CPP-GMR read sensors, however, achieving large CPP-GMR output using polycrystalline films annealed at a lower temperature (currently, ~300 °C) is important. Recently, Choi et al. [3] reported that CPP-GMR ratio of spin-valves using polycrystalline Heusler alloy layers could be improved by inserting thin (< 1 nm) amorphous CoFeBTa underlayer below the Heusler alloy layer. In addition, the non-magnetic spacer layer of CPP-GMR device has a great potential for improving the CPP-GMR value. Especially, a InZnO (IZO) conductive oxide-based spacer layer [5] is promising because of the slightly increased RA to ~0.1 Ω μm2, which is optimal for read sensor application for 2 Tbit/in2 [4], and the improved MR ratio ~25% achieved in practical spin-valve sensor structure. In this presentation, we review our recent studies to understand the mechanisms of MR enhancements by (i) CoFeBTa amorphous underlayer inserted below Heusler alloy magnetic layer, and (ii) Ag/IZO/Zn spacer layer using synchrotron x-ray diffraction and electron microscopy. |
| File Format | PDF HTM / HTML |
| Alternate Webpage(s) | https://www.nims.go.jp/mmu/tmrc2017/att/B3.pdf |
| Language | English |
| Access Restriction | Open |
| Content Type | Text |
| Resource Type | Article |
