• Title/Summary/Keyword: MgO underlayer

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The Role of (111)MgO Underlayer in Growth of c-axis Oriented Barium Ferrite Films

  • Erickson, D.W.;Hong, Y.K.;Gee, S.H.;Tanaka, T.;Park, M.H.;Nam, I.T.
    • Journal of Magnetics
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    • v.9 no.4
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    • pp.116-120
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    • 2004

  • Hexagonal barium-ferrite ($BaFe_{12}O_{19}$, magnetoplumbite structure; BaM) film with perpendicularly c-axis orientation was successfully deposited on (100) silicon substrates with an MgO (111) underlayer by rf diode sputtering and in-situ heating at $920^{\circ}C$. The magnetic and structural properties of 0.27 ${\mu}m$ thick BaM films on MgO (111) underlayers were compared to films of the same thickness deposited onto single-crystal MgO (111) and c-plane ($000{\ell}$) sapphire ($Al_2O_3$) substrates by vibrating sample magnetometry (VSM), x-ray diffractometer (XRD), and atomic force microscopy (AFM). The thickness dependence of MgO (111) underlayers on silicon wafer was found to have a large effect on both magnetic and structural properties of the BaM film. The thickness of 15 nm MgO (111) underlayers produced BaM films with almost identical magnetic and structural properties as the single-crystal substrates; this can be explained by the lower surface roughness for thinner underlayer thicknesses. The magnetization saturation ($M_s$) and the ratio $H_{cII}/H_{c{\bot}}$ for the BaM film with a 15 nm MgO (111) underlayer is 217 emu/cc and 0.24, respectively. This is similar to the results for the BaM films deposited on the single-crystal MgO (111) and sapphire substrates of 197 emu/cc and 0.10, 200 emu/cc and 0.12, respectively. Therefore, the proposed MgO (111) underlayer can be used in many applications to promote c-axis orientation without the cost of expensive substrates.

  • https://doi.org/10.4283/JMAG.2004.9.4.116 인용 PDF KSCI

Study on Effect of Various Underlayer on Bilayer Agglomerlation (다양한 하지층이 이중층의 응집현상에 미치는 영향에 관한 연구)

  • Ha, J.H.;Ryu, D.H.;Im, H.W.;Jung, J.M.;Choi, H.J.;Hong, I.G.;Koh, J.H.;Koo, S.M.;Kamiko, M.;Ha, J.G.
    • Journal of the Korean Vacuum Society
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    • v.21 no.5
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    • pp.233-241
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    • 2012

  • We have deposited the bilayer consisted of the underlayer and the overlayer by using DC magnetron sputter on Single crystal MgO (001) substrate. This bilayer was fabricated at fixed annealing temperature and time. We have controlled agglomeration effect by changing of the bilayer thickness. Finally, we have made the self-organization and nano-structured film. In this processing, we have made nano-dot which consists of the underlayer and the overlayer, unlike the existing method called the agglomeration effect in the single layer. The underlayer has deposited using Ti, Cr and Co. And the overlayer has deposited with Ag. Through the analysis of Atomic force microscopy (AFM), the microstructure of underlayer is observed by AFM to confirm the formation of nano-dot. As the nano-dot through above processing, we have found that the nano-dot has the different shape. As a result, when we manufactured nano-dot through the agglomeration effect of bi-layer, the best matching material is Ti for underlayer. And also, we have found that MgO/Ti/Ag samples have been grown expitaxially toward the direction of MgO (001) by X-ray Diffraction analysis.

  • https://doi.org/10.5757/JKVS.2012.21.5.233 인용 PDF KSCI