Ordering Transformation and Magnetic Study of Cu-alloyed CoPt Thin Films

• Main Authors: Yu-Peng Lin, 林宥朋
• Other Authors: S. K. Chen
• Format: Others
• Language: zh-TW
• Published: 2003
• Online Access: http://ndltd.ncl.edu.tw/handle/vgp9ck

碩士 === 逢甲大學 === 材料科學所 === 91 === CoxPt100-x (x= 85, 63, 52, 37) thin films were deposited on quartz substrates with a high vacuum RF sputtering system. The thickness was 100 nm and the films were annealed in-situ from 400℃ to 800℃. The hard magnetic proprieties are promoted by the addition of Pt and the best coercivity of 11 kOe was obtained in Co52Pt48 thin films annealed at 800℃. We have studied the effect of Cu on Co52Pt48 thin films by Cu underlayer or by directly adding Cu element in the thin films. The x-ray diffraction patterns showed that the Co52Pt48/Cu samples exhibit stronger peaks of ordered CoPt phase, indicating the effect of ordering enhancement by Cu element. Coercivities of the CoPt and CoPt/Cu films annealed at 650℃ for 10 minutes are 2.6 kOe and 5.1 kOe, respectively. The higher coercivity can be attributed to the ordering enhancement by Cu underlayer. The δM value of CoPt/Cu film is 60% smaller than that of single-layer CoPt. It shows that Cu underlayer may decrease the exchange interaction in the CoPt magnetic layer. The Cu doped CoPt (CoPtCu) samples also shows a promoted ordering transformation. The coercivity are 4.1 kOe for CoPtCu and 2.0 kOe for CoPt after annealed at 550℃. The ordering temperature of CoPtCu film is 100℃ lower than that of CoPt film. X-ray diffraction of CoPtCu film shows stronger ordered CoPt peaks. The Cu element could promote the ordering of CoPt thin films no matter for Cu underlayer or directly adding to the films. Comparing the above two methods, the CoPt/Cu sample shows a strong enhancement in ordered CoPt (001) XRD line, while CoPtCu sample shows a strong effect in decreasing the ordering temperature.