Fabrication and magnetic properties of single-layered FePt thin films with perpendicular magnetic anisotropy

• Main Authors: Ta-Huang Sun, 孫達皇
• Other Authors: Sheng-Chi Chen
• Format: Others
• Language: zh-TW
• Published: 2010
• Online Access: http://ndltd.ncl.edu.tw/handle/72528726742059715577

碩士 === 明志科技大學 === 材料工程研究所 === 98 === In this study, we investigate the effect of rapid thermal annealing and in-situ annealing on microstructures and magnetic properties of single-layered FePt films. PartⅠ: The single-layered FePt films with thickness in the range of 5 to 50 nm are deposited directly on Si(100) substrate without underlayer, then post annealed at 700°C for 3 min by rapid thermal annealing (RTA) with a high heating ramp rate of 100°C /sec. As the film thickness of FePt is over 30 nm, the L10 FePt(111) preferred orientation is presented and tended to in-plane magnetic anisotropy. However, the L10 FePt(001) texture is obtained and exhibited perpendicular magnetic anisotropy as the film thickness is decreased to 10 nm. Its perpendicular coercivity (Hc⊥), saturation magnetization (Ms) and perpendicular squareness (S⊥) are 14.8 kOe, 795 emu/cm3 and 0.79, respectively. On the other hand, both the grain size and domain size of FePt film decrease with decreasing the film thickness of FePt. The grain size for 10-nm FePt film is as small as 9.7 nm with domain size of 123 nm, which reveal its significant potential as perpendicular magnetic recording media for ultra high-density recording. PartⅡ: the single-layered FePt films with various substrate temperatures, Pt contents and thickness are deposited by in-situ annealing and the effect of substrate temperature, Pt content and film thickness on microstructures and magnetic anisotropy of FePt films are investigated. The FePt films with various thicknesses of 5 to 50 nm are deposited on Si(100) substrate without any underlayer by in-situ annealing at substrate temperature (Ts) of 620°C. A strong (001) texture of L10 FePt film is obtained and presents high perpendicular magnetic anisotropy as the film thickness increases to 30 nm. Further increasing the thickness to above 30 nm, the (111) orientation of L10 FePt is enhanced greatly, indicating that the quality of perpendicular magnetic anisotropy degrades when the FePt film is thicker than 30 nm. The single-layered FePt film with thickness of 30 nm by in-situ depositing at 620°C shows good perpendicular magnetic properties (perpendicular coercivity of 14.0 kOe, saturation magnetization of 473 emu/cm3 and perpendicular squareness of 0.96, respectively), which reveal its significant potential as perpendicular magnetic recording media for high-density recording.