C-axis Oriented Bafe <sub> 12 </ Sub> O <sub> 19 </ Sub> Thin Film Integrated Into The Magnetron Sputtering Process And Performance Of The Si Single Crystal Substrate

M-type barium ferrite (BaFe₁₂O₁₉, BaM) has been widely used in high density magnetic recording media,permanent magnets, microwave devices, and so on, due to its superior chemical stability, mechanical hardness, anti-erosion and high perpendicular magnetic anisotropy. The next generation of magnetic recording media and magnetic microwave devices will be planar, thus BaM thin films have been studied intensivly. It is vitally important to obtain c-axis oriented BaM thin films in order to improve recording density or reach very narrow ferromagnetic resonance (FMR) linewidth. In this article, we focused on the radio frequency magnetron sputtering conditions of growing c-axis oriented BaM thin films on silicon substrates, and the effects of different underlayers to the BaM orientation, microstrcture, magnetic property and microwave property.It is difficult to prepare epitaxial c-axis preferential oriented BaM thin films on Si (100) substrates directly. However, the excellent c-axis oriented BaM thin films(360 nm) could be prepared on Si substrates with underlayer Pt of a thickness from 10-60 nm, When the thickness of Pt underlayer was 30 nm, the average BaM grain size was about 400 nm, the perpendicular coercivity Hc⊥and squareness(Mr⊥/Ms⊥) reached 833 Oe and 0.35, respectively. The microwave measurement showed that the sample with 20 nm pt underlayer revealed the lowest ferromagnetic resonance (FMR) linewidth ?H= 399 Oe at 44 GHz. Finally, c-axis oriented BaM thin films prepared on silicon substrates with yttria-stabilized-zirconia (YSZ) (111) underlayer, showed very fine grains and higher coercivity Hc⊥and squareness(2200 Oe and 0.87) than that with Pt underlayer, and have great potentiality for recording application.