| Summary: | 碩士 === 元智大學 === 化學工程與材料科學學系 === 101 === Co-Pt alloy series ordering phases are well known due to their high magnetocrystalline anisotropy constant (usually in the order of 107 erg/cm3) and outstanding magnetic properties. However, high ordering temperatures of L10-CoPt and L12-CoPt3 phases induce large magnetic grains and drastic interlayer diffusion. Besides, using high amount of costly Pt is also the drawback for application. Therefore, low temperature processing Co3Pt phase with m-D019 structure was prepared on Pt (or Ru) underlayers on glass substrates by an ultra-high vacuum sputtering system in this study.
Perpendicular magnetic behaviors of Co3Pt thin films could be enhanced by insertion a Pt underlayer, because the formation of the superlattice Co3Pt(00.1) with m-D019 HCP structure in the film. However, the magnetic properties still need to be improved. Broader superlattice peak Co3Pt (00.1) was formed owing to large lattice misfit (11%) between Co3Pt and Pt layer.
As replace the Pt underlayer with Ru underlayer, Co3Pt film show the magnetic isotropy at each annealing temperature, which is opposite result to Co3Pt films on Pt underlayer. The perpendicular magnetic anisotropy (PMA) was remarkably declined. SEM images implied that the Pt underlayer surface was much smoother than that on Ru underlayer, which was the key effect to influence the growth of m-D019 Co3Pt structure with the perpendicular magnetic behaviors.
Combination of a Ru buffer layer and Pt underlayer enhances the ordering phase of m-D019 Co3Pt structure largely, because the superlattice Co3Pt(00.1) peak is much sharper than the peak of Co3Pt/Pt/Glass. Therefore, Ru (00.2) orientation could be well grown by Pt(111), which induces formation of m-D019 Co3Pt structure in Co3Pt/Ru/Pt/glass film structure. The formation mechanism of m-D019 structure in Co3Pt film will be discussed in detail.
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