| Summary: | 碩士 === 元智大學 === 化學工程與材料科學學系 === 100 === Most of current L11-CoPt thin films were deposited on MgO substrate for obtaining the epitaxially grown L11 structure. However, the ultrahigh price of MgO substrate does not match the manufacture process. In order to reduce the cost, this study investigated the replacement of MgO substrate with glass substrate. Samples were fabricated by magnetron sputtering under the ultra-high vacuum environment. The CoPt film was grown by rotational co-sputtering with equiatomic CoPt condition on an amorphous glass substrate at 350 ℃. The magnetic properties and microstructure of CoPt film on glass substrates were discussed.
In this study, CoPt film has lower coercivity (Hc~0.5 kOe) and in-plane magnetic anisotropy on glass substrate without inserting a Pt underlayer. When a Pt underlayer is added between magnetic film and glass substrate, the magnetic properties are obviousily improved, not only enhanced the coercivity but also altered the perpendicular anisotropy. Additional, the Hc of CoPt film is strongly increased with decreaseing the thickness of CoPt layer. When the thickness of CoPt is reduced to 3 nm, the coercivity is increase to 1.78 kOe. In order to further improve the magnetic properties of L11-CoPt, sputtering condition of Pt underlayer was systemly studied. First of all, we change the annealing time of Pt underlayer (5 min~30 min), and then the annealing temperature of Pt underlayer (200 ℃ ~ 500 ℃), and aim the thickness to adjust (5 nm ~ 30 nm). The optimun conditions for depositing Pt unserlayer are 20 nm to 25 nm and annealing at 350 ℃ for 15 min, at this condition the L11-CoPt film obtains the higher Hc of 2.49 kOe ~2.56 kOe.
Glass substrate replaces expensive MgO(111) substrate in our study. Except successfully fabricate L11-CoPt on glass, we also enhance the magnetic properies of CoPt film by adjusting the sputtering condition of Pt underlayer. The presented results have great potential for future magnetic recording midea application.
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