Microstructures and Magnetic Properties of ${rm CoPt{-}SiN}_{x} {-}{rm Ag}$ Granular Thin Films With Ag Underlayer

摘要

When the Ag layer was introduced under the CoPt alloy film which annealed at 700 $^{circ}{rm C}$ , the CoPt/Ag films had large out-of-plane squareness $({S}_{perp})$, out-of-plane coercivity $({H}_{{c}perp})$, and saturation magnetization $({M}_{s})$ . They were 0.95, 1432 kA/m, and 390 ${rm emu/cm}^{3}$, respectively. Further, the ${rm SiN}_{x}$ ceramic materials were cosputtered with CoPt on the Ag underlayer at room temperature and then annealed to reduce the grain size of CoPt films. From the field-emission gun high-resolution transmission electron microscope analysis, the particle size of CoPt was about 10 nm as the ${rm SiN}_{x}$ content was 46.2 vol.%. Furthermore, Ag was added into the ${rm CoPt{-}SiN}_{x}$ films to reduce the transformation temperature of CoPt films from face-centered-cubic to face-centered-tetragonal structure.