Dot arrays of L1{sub 0}-type FePt ordered alloy perpendicular films fabricated using low-temperature sputter film deposition

Journal Article · Fri Apr 01 00:00:00 EDT 2011 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.3556697· OSTI ID:21560102

Shimatsu, T; Aoi, H ^[1]; Inaba, Y; Kataoka, H ^[1]; Sayama, J ^[2]; Okamoto, S; Kitakami, O ^[3]

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1. Research Institute of Electrical Communication, Tohoku University, Sendai, 980-8577 (Japan)
2. Central Research Laboratory, Hitachi, Ltd., Kanagawa, 256-8510 (Japan)
3. Institute of Multidisciplinary Research for Advanced Material, Tohoku University, Sendai, 980-8577 (Japan)

Using ultrahigh vacuum sputter film deposition, we fabricated L1{sub 0}-type Fe{sub 50}Pt{sub 50} ordered alloy perpendicular films on MgO(001) single-crystal substrates and 2.5 in. glass disks at low substrate temperatures of 200-350 deg. C. Then we examined the magnetic properties of the dot arrays made from these films. The uniaxial magnetic anisotropy K{sub u} for L1{sub 0}-type FePt films (10 nm in thickness) deposited with a Pd underlayer on MgO(001) substrates reached about 2 x 10{sup 7} erg/cm{sup 3} at the substrate temperature T{sub s} of 200 deg. C, and 3 x 10{sup 7} erg/cm{sup 3} at T{sub s} = 250 deg. C. The order parameter S was about 0.46 at T{sub s} = 300 deg. C. Moreover, K{sub u} for L1{sub 0}-FePt films fabricated on glass disks using MgO/Cr underlayers shows 3.4 x 10{sup 7} erg/cm{sup 3} at T{sub s} = 300 deg. C, which was almost equal to that for FePt single-crystal films deposited on Pd/MgO(001). The switching field distribution {sigma}/H{sub c} for dot arrays made from L1{sub 0}-FePt film [5 nm in thickness, on Pd/MgO(001) at T{sub s} = 250 deg. C] was small; {sigma}/H{sub c}= 0.11 for a dot diameter of 15 nm. This value was smaller than that of hcp-Co{sub 75}Pt{sub 25} dot arrays ({sigma}/H{sub c} = 0.18). The difference was mainly attributable to the degree of the easy axis distribution. This result demonstrates the homogeneous formation of a L1{sub 0}-type ordered structure in the FePt layers.

• OSTI ID: 21560102
• Journal Information: Journal of Applied Physics, Vol. 109, Issue 7; Conference: 55. annual conference on magnetism and magnetic materials, Atlanta, GA (United States), 14-18 Nov 2010; Other Information: DOI: 10.1063/1.3556697; (c) 2011 American Institute of Physics; ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ANISOTROPY
DISTRIBUTION
GLASS
HCP LATTICES
IRON ALLOYS
LAYERS
MAGNESIUM OXIDES
MAGNETIC PROPERTIES
MONOCRYSTALS
ORDER PARAMETERS
PLATINUM ALLOYS
SPUTTERING
SUBSTRATES
THICKNESS
THIN FILMS
VACUUM COATING
ALKALINE EARTH METAL COMPOUNDS
ALLOYS
CHALCOGENIDES
CRYSTAL LATTICES
CRYSTAL STRUCTURE
CRYSTALS
DEPOSITION
DIMENSIONLESS NUMBERS
DIMENSIONS
FILMS
HEXAGONAL LATTICES
MAGNESIUM COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
PLATINUM METAL ALLOYS
SURFACE COATING
TRANSITION ELEMENT ALLOYS