TY - JOUR
T1 - Large uniaxial magnetic anisotropy by lattice deformation in CoPt/Ru perpendicular films
AU - Shimatsu, T.
AU - Sato, H.
AU - Okazaki, Y.
AU - Aoi, H.
AU - Muraoka, H.
AU - Nakamura, Y.
AU - Okamoto, S.
AU - Kitakami, O.
N1 - Funding Information:
This work is partially supported by the IT-program (RR2002) of Ministry of Education, Culture, Sports, Science and Technology (MEXT) of Japan.
PY - 2006
Y1 - 2006
N2 - A large uniaxial magnetic anisotropy Ku of about 2× 107 erg cm3 was obtained in Co-(20-30) at. % Pt perpendicular films deposited on Ru seed layers. The films showed good c -axis orientation perpendicular to the film plane, and no evidence of a Co3 Pt -type-ordered structure was found in the X-ray-diffraction patterns. The value of Ku (the sum of the first- and second-order terms of uniaxial anisotropy, Ku1 and Ku2) increased as the thickness of the CoPt layer decreased, and reached about 2× 107 erg cm3 at 2 nm (Co-20 at. % Pt films) or 5 nm (Co-(25-30) at. % Pt films). The ratio of Ku2 to Ku1 was 0.16 in 40 nm films, but reduced to less than 0.03 for thicknesses below 5 nm. The experimental results suggest that, besides the surface anisotropy, the increase in Ku on reducing the thickness is mostly related to the reduction of the hcp-CoPt lattice ca ratio, probably due to epitaxial growth of CoPt on the Ru seed layer.
AB - A large uniaxial magnetic anisotropy Ku of about 2× 107 erg cm3 was obtained in Co-(20-30) at. % Pt perpendicular films deposited on Ru seed layers. The films showed good c -axis orientation perpendicular to the film plane, and no evidence of a Co3 Pt -type-ordered structure was found in the X-ray-diffraction patterns. The value of Ku (the sum of the first- and second-order terms of uniaxial anisotropy, Ku1 and Ku2) increased as the thickness of the CoPt layer decreased, and reached about 2× 107 erg cm3 at 2 nm (Co-20 at. % Pt films) or 5 nm (Co-(25-30) at. % Pt films). The ratio of Ku2 to Ku1 was 0.16 in 40 nm films, but reduced to less than 0.03 for thicknesses below 5 nm. The experimental results suggest that, besides the surface anisotropy, the increase in Ku on reducing the thickness is mostly related to the reduction of the hcp-CoPt lattice ca ratio, probably due to epitaxial growth of CoPt on the Ru seed layer.
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U2 - 10.1063/1.2167351
DO - 10.1063/1.2167351
M3 - Article
AN - SCOPUS:33646749869
SN - 0021-8979
VL - 99
JO - Journal of Applied Physics
JF - Journal of Applied Physics
IS - 8
M1 - 08G908
ER -