PT J
AU Wodarz, S
   Hasegawa, T
   Ishio, S
   Homma, T
AF Wodarz, Siggi
   Hasegawa, Takashi
   Ishio, Shunji
   Homma, Takayuki
TI Structural control of ultra-fine CoPt nanodot arrays via
   electrodeposition process
SO JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS
LA English
DT Article
DE Electrodeposition; Structural control; Nanodot array; Bit-patterned
   media; CoPt alloy
ID BIT-PATTERNED MEDIA; ELECTRON-BEAM LITHOGRAPHY; RECORDING MEDIA;
   MAGNETIC MEDIA; DENSITY; FILMS; ANISOTROPY; STORAGE
AB CoPt nanodot arrays were fabricated by combining electrodeposition and electron beam lithography (EBL) for the use of bit-patterned media (BPM). To achieve precise control of deposition uniformity and coercivity of the CoPt nanodot arrays, their crystal structure and magnetic properties were controlled by controlling the diffusion state of metal ions from the initial deposition stage with the application of bath agitation. Following bath agitation, the composition gradient of the CoPt alloy with thickness was mitigated to have a near-ideal alloy composition of Co:Pt =80:20, which induces epitaxial-like growth from Ru substrate, thus resulting in the improvement of the crystal orientation of the hcp (002) structure from its initial deposition stages. Furthermore, the cross-sectional transmission electron microscope (TEM) analysis of the nanodots deposited with bath agitation showed CoPt growth along its c-axis oriented in the perpendicular direction, having uniform lattice fringes on the hcp (002) plane from the Ru underlayer interface, which is a significant factor to induce perpendicular magnetic anisotropy. Magnetic characterization of the CoPt nanodot arrays showed increase in the perpendicular coercivity and squareness of the hysteresis loops from 2.0 kOe and 0.64 (without agitation) to 4.0 kOe and 0.87 with bath agitation. Based on the detailed characterization of nanodot arrays, the precise crystal structure control of the nanodot arrays with ultra-high recording density by electrochemical process was successfully demonstrated.
C1 [Wodarz, Siggi; Homma, Takayuki] Waseda Univ, Dept Appl Chem, Shinjuku Ku, Tokyo 1698555, Japan.
   [Hasegawa, Takashi; Ishio, Shunji] Akita Univ, Dept Mat Sci, Akita 0108502, Japan.
RP Homma, T (reprint author), Waseda Univ, Dept Appl Chem, Shinjuku Ku, Tokyo 1698555, Japan.
EM t.homma@waseda.jp
OI Hasegawa, Takashi/0000-0002-8178-4980
FU JSPS KAKENHI Grant [25249104]
FX This work was supported in part by JSPS KAKENHI Grant Number 25249104.
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NR 28
TC 0
Z9 0
U1 21
U2 21
PU ELSEVIER SCIENCE BV
PI AMSTERDAM
PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS
SN 0304-8853
EI 1873-4766
J9 J MAGN MAGN MATER
JI J. Magn. Magn. Mater.
PD MAY 15
PY 2017
VL 430
BP 52
EP 58
DI 10.1016/j.jmmm.2017.01.061
PG 7
WC Materials Science, Multidisciplinary; Physics, Condensed Matter
SC Materials Science; Physics
GA EP2GP
UT WOS:000397201600008
ER
