CoTb/FePt 熱寫磁讀紀錄薄膜之研製

Abstract

本實驗以直流磁控濺鍍，於自然氧化的矽晶圓(100)基板和康寧玻璃基板上鍍製200 Å的FePt合金薄膜當做底層，再同樣以直流磁控濺鍍的方法鍍製500 Å的CoTb合金薄膜於FePt底層上面，最後以射頻磁控濺鍍在CoTb薄膜上濺鍍一層300 Å的SiNx保護層，避免CoTb合金薄膜氧化。本實驗先固定CoTb合金薄膜的組成比例，然後以不同製程條件鍍製FePt底層，探討其對於CoTb/FePt合金薄膜磁性質的影響。 經XRD和TEM分析結果，底層的FePt磁性薄膜有（111）及（001）兩種不同的從優取向，上層的CoTb合金薄膜為非晶質結構。實驗結果顯示無論加入的底層為（111）從優取向的FePt磁性薄膜或（001）從優取向的FePt磁性薄膜，Co70.44Tb29.56/FePt 磁性薄膜飽和磁化強度（Ms）以及垂直方向的矯頑磁力（Hc⊥）都比單層Co70.44Tb29.56磁性薄膜的Ms、Hc⊥大，其中加入（001）從優取向的FePt磁性底層可使雙層Co70.44Tb29.56/FePt 磁性薄膜具有垂直膜面之磁異向性。 實驗結果顯示，加入（001）從優取向的FePt磁性薄膜當作CoTb合金薄膜的底層後，具有高的Ms及Hc⊥值。其Ms＝403 emu/cm3、Hc⊥＝5450 Oe，具有應用於新型熱寫磁讀記錄媒體的潛力。

DC magnetron sputtering is used to deposit 200 Å Fe50Pt50 film on the naturally oxidized Si (100) and glass substrates at various substrate temperatures , then deposited 500 Å Co70.44Tb29.56 film on the FePt film. Finally, a SiNx film with thickness of 300 Å is deposited on the Co70.44Tb29.56 film by RF magnetron sputtering, to protect the Co70.44Tb29.56 film from oxidation. The manufacturing conditions of FePt underlayer are varied to investigate their effects on the magnetic properties of CoTb/FePt films. From X-ray and TEM analyzing, FePt underlayer has（111）and （001）two different preferred orientations, and the CoTb film has amorphous structure. We find that whatever the preferred orientation of the FePt film is （111）or （001）, the saturated magnetization （Ms）and the perpendicular coercivity （Hc⊥）of the Co70.44Tb29.56/FePt films are higher than those of the single layered Co70.44Tb29.56 film. The magnetic anisotropy of the bilayer Co70.44Tb29.56/FePt（001）films is perpendicular to the film plane. Using FePt（001）film as underlayer, Ms and Hc⊥ of the Co70.44Tb29.56/FePt（001） films are 403 emu/cm3 and 5450 Oe respectively. This bilayer films has high Hc⊥ and Ms values, it has potential to apply in the recording media of heat-assisted magnetic recording.