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Enhancement of CPP-GMR ratio by Ag-In-Zn-O precursor for spacer layer
| Content Provider | Semantic Scholar |
|---|---|
| Author | Nakatani, Tomoya Sasaki, Taisuke Sakuraba, Yuya Hōno, Kazuhiro |
| Copyright Year | 2019 |
| Abstract | Enhancing the output of current-perpendicular-to-plane giant magnetoresistance (CPP-GMR) devices is the critical issue for the nano-scale magnetic sensor applications such as read sensors of hard disk drives. The selection of the material for the non-magnetic spacer layer is important for improving CPP-GMR ratio. We recently reported MR ratios (ΔR/R) up to 30% with spin-valve devices by using Ag/In-Zn-O (IZO)/(Zn) bior tri-layer as spacer, which works as a precursor to form heterogeneous Ag-In:Mn-Zn-O nanocomposite spacer layer. [1] In this presentation, we report improved CPP-GMR ratios by using Ag-In-Zn-O (AIZO) as the spacer layer of the CPP-GMR devices with polycrystalline Co2(Mn0.6Fe0.4)Ge (CMFG) Heusler alloy ferromagnetic layers. Pseudo spin-valve stacks of Ta(2)/Ru(2)/CoFe(0.5)/CoFeBTa(1.5)/CMFG(5)/CoFe(0.4) /spacer/CoFe(0.4)/CMFG(5)/CoFeBTa(1.5)/Ru(8) (in nm) were sputter-deposited on Cu bottom-lead fabricated on thermally oxidized Si substrate. AgSn(3.5 m), Ag(0.4 nm)/IZO(1.30-1.75 nm), and AIZO(1.2 nm) with nominal Ag concentrations of 20-36 at. % were used for the spacer layer. The films were annealed at 280 °C for 3 h and patterned to CPP-pillar devices. Figure 1 shows RA and ΔR/R of the devices. A large ΔR/R up to 54% at RA ~0.075 Ω μm was obtained by using the AIZO with Ag 29 at. % spacer precursor, which is much larger than those by the Ag/IZO spacer precursor (up to 35%). Scanning transmission electron microcopy revealed that the actual spacer layer by the AIZO precursor was a Ag-In:Mn-Zn-O nanocomposite, similar to that by the Ag/IZO/Zn precursor. [1] Thus, the mechanism of the RA and ΔR/R enhancements by the AIZO spacer precurso is thought to be current-confinement effect by the Ag-In metallic paths in the spacer layer. The larger ΔR/R by the AIZO precursor than those by the Ag/IZO precursor could be understood by assuming a formation of Ag-In metallic paths with a lower resistivity. References [1] Nakatani et al. IEEE Trans. Magn. 54, 3300211 (2018), J. Appl. Phys. 124, 223904 (2018). |
| File Format | PDF HTM / HTML |
| Alternate Webpage(s) | https://confit.atlas.jp/guide/event-img/jsap2019s/11p-M101-19/public/pdf?type=in |
| Language | English |
| Access Restriction | Open |
| Content Type | Text |
| Resource Type | Article |
