Electrodeposition of (001) oriented CoPt L10 columns into anodic alumina films

Yasui, Norio; Imada, Aya; Den, Tohru

doi:10.1063/1.1622787

Cited by 114 publications

(75 citation statements)

References 11 publications

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“…12 There are recent reports of electrodeposition of ferromagnetic metals and alloys into nanoporous membranes. [13][14][15] Some coercivity ͑0.16 T͒ has been reported for cobalt deposited into alumina templates, and there are recent reports of Co-Pt nanotubes 16 and nanowires 17,18 with interesting hysteretic properties prepared in this way.…”

Section: Introductionmentioning

confidence: 99%

Thick-film permanent magnets by membrane electrodeposition

Rhen¹,

Backen²,

Coey³

2005

Journal of Applied Physics

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Thick films of nearly equiatomic Co-Pt produced by electrodeposition into nanoporous membranes exhibit an isotropic magnetic phase with square hysteresis loops ͑M r / M s = 0.95͒ and coercivity of up to 1.3 T. The initial magnetization curve is characteristic of pinning-type magnets. The coercivity can be controlled by the choice of annealing temperature or alloy composition, which depends on the chemical composition of the plating bath, properties which can be exploited to produce fine-pitch pole patterns.

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Section: Introductionmentioning

confidence: 99%

Thick-film permanent magnets by membrane electrodeposition

Rhen¹,

Backen²,

Coey³

2005

Journal of Applied Physics

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“…8) This result was achieved with film thicknesses from 200-500 nm with a diameter of several dozen nanometers. Although we tried to make a thin recording layer of below 25 nm, there were some difficulties: 1) High-Ku materials like L10-CoPt and L10-FePt had to be used as embedding magnetic materials because shape anisotropy was not available; 2) Over-and under-polishing could not be ignored.…”

Section: Serious Problems In Embedded Type Patterned Media Fabricationmentioning

confidence: 80%

“…8) The oxide creation type was obtained using an underlayer material of Ti, Nb, W, etc., and had an underlayer material oxide at the bottom of the holes. On the other hand, the penetration type was obtained with an underlayer material such as Pt, Pd, or Cu, and did not have any substances at the bottom of the holes after the pore-widening process.…”

Section: Serious Problems In Embedded Type Patterned Media Fabricationmentioning

confidence: 99%

Fabrication of 1 Tdots/in2 Patterned Media with Anodic Alumina Technique

et al. 2008

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We investigated the potential of an anodic alumina template for high-density patterned media. Anodic alumina hole density of 1.86 Tdots/in 2 was achieved by suppressing surface roughness by alloying aluminum with Ti and Hf. However, it was difficult to fabricate the embedded type patterned media with a recording layer of thinner than 25 nm in an anodic alumina template of 1.03 Tdots/in 2 . This necessitated a switch from an embedding process to a coating process, so we developed a new anodizing process for patterned media of 1 Tdots/in 2 . The process formed the niobium oxide pillar structure successfully with high density in an anodic alumina template. 1.03 Tdots/in 2 patterned media fabrication was achieved by depositing the Co70Pt30 recording layer on the pillars.

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“…[6][7][8] One-dimensional nanowire arrays based on anodic aluminum oxide ͑AAO͒ present an attractive potential medium because when deposited the wires comprise a highly ordered pattern of magnetically isolated units. [9][10][11] Although only a few reports are current for CoPt nanowire materials, [12][13][14] the highest squareness ratio of CoPt nanowire embedded in AAO with a wire diameter of 80 nm has been claimed by Yasui et al as 0.96. 14 We have recently prepared electrodeposited Co ͑1−x͒ Pt x nanowire arrays having a factor of 6 smaller wire diameter compared with wires reported by Yasui et al 14 As a first step in this study, we concentrate on Co 96 Pt 4 Co-rich nanowire arrays that were annealed up to 800°C under the protection of nitrogen in a rapid thermal annealing system.…”

Section: Introductionmentioning

confidence: 99%

Co-rich cobalt platinum nanowire arrays: Effects of annealing

Peng

Jones

et al. 2005

Journal of Applied Physics

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The effects of annealing on the crystal structure and magnetic properties of Co-rich cobalt platinum nanowire arrays embedded in anodic aluminium oxide membranes have been investigated. For this purpose, a rapid thermal annealing to temperatures of 300°C to 800°C has been used. Transmission electron microscopy and scanning electron microscopy show that the nanowires have a mean diameter of 14 nm and an estimated wire density of 7.8ϫ 10 10 cm −2 . From x-ray diffraction patterns, we find that the nanowires are hcp and possess a preferred texture in which the c axis of the grains tends to lie along the major axis of the wire. Vibrating sample magnetometry measurements indicate that the easy axis is along the nanowire axis direction. Hysteresis loops, saturation magnetization, squareness ratio ͑M r / M s ͒, and coercivity ͑perpendicular and parallel to the nanowire axis͒ have all been investigated as a function of the annealing temperature ͑T A ͒. Coercivity parallel to the wire axis first increases with T A , attains a maximum at 600°C ͑which is 150% of the as-deposited sample͒, and then decreases. By contrast there is relatively little change in the coercivity measured perpendicular to the wires. The saturation magnetization for the as-deposited sample is 1360 emu/ cc and remains almost constant for annealing temperatures up to 500°C: for T A Ͼ 500°C it decreases significantly. The maximum ͑M r / M s ͒ ratio attained in this study is 0.99, the highest value reported thus far for cobalt platinum alloy nanowires. The data suggest that these materials are potential candidates for high-density magnetic recording media.

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Electrodeposition of (001) oriented CoPt L10 columns into anodic alumina films

Cited by 114 publications

References 11 publications

Thick-film permanent magnets by membrane electrodeposition

Thick-film permanent magnets by membrane electrodeposition

Fabrication of 1 Tdots/in2 Patterned Media with Anodic Alumina Technique

Co-rich cobalt platinum nanowire arrays: Effects of annealing

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