Effect of MgO underlayer misorientation on the texture and magnetic property of FePt–C granular film

Wang, Jian; Hata, Satoshi; Takahashi, Y. K.; Sepehri-Amin, H.; Varaprasad, B. S. D. Ch. S.; Shiroyama, T.; Schrefl, T.; Hono, K.

doi:10.1016/j.actamat.2015.03.007

Cited by 50 publications

(30 citation statements)

References 35 publications

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“…After deposition, the samples were processed by rapid thermal annealing (RTA) at 700 C for 30 s in N 2 atmosphere. It has been demonstrated that RTA processing of FePt/Cu bilayers does not only lead to chemical ordering but also to the development of a (001) texture on amorphous substrates, [41][42][43][44][45][46][47][48][49][50][51][52][53][54][55][56]68 which reveals the high potential of an RTA process for the fabrication of future FePt-based devices.…”

Section: B Fecupt/fe Ecc Mediamentioning

confidence: 99%

See 1 more Smart Citation

Review Article: FePt heat assisted magnetic recording media

Weller¹,

Parker²,

Mosendz³

et al. 2016

Journal of Vacuum Science &Amp; Technology B, Nanotechnology and Microelectronics: Materials, Processing, Measurement, and Phen

159

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Heat-assisted magnetic recording (HAMR) media status, requirements, and challenges to extend the areal density (AD) of magnetic hard disk drives beyond current records of around 1.4 Tb/in.2 are updated. The structural properties of granular high anisotropy chemically ordered L10 FePtX-Y HAMR media by now are similar to perpendicular CoCrPt-based magnetic recording media. Reasonable average grain diameter ⟨D⟩ = 8–10 nm and distributions σD/D ∼ 18% are possible despite elevated growth temperatures TG = 650–670 °C. A 2× reduction of ⟨D⟩ down to 4–5 nm and lowering σD/D < 10%–15% are ongoing efforts to increase AD to ∼4 Tb/in.2. X = Cu ∼ 10 at. % reduces the Curie temperature TC by ∼100 K below TC,bulk = 750 K, thereby lowering the write head heat energy requirement. Multiple FePtX-Y granular layers with Y = 30–35 vol. % grain-to-grain segregants like carbides, oxides, and/or nitrides are used to fully exchange decouple the grains and achieve cylindrical shape. FePt is typically grown on fcc MgO (100) seedlayers to form well oriented FePt (002). A FePt lattice parameter ratio c/a ∼0.96 and high chemical order S > 0.90 result in magnetic anisotropy KU ∼ 4.5 × 107 erg/cm3, and only 25% below the FePt single crystal value KU = 6.6 × 107 erg/cm3 has been achieved in 7–8 nm diameter grains. Switching field distributions depend on anisotropy field (HK) distributions, which are currently of the order of ΔHK/HK ∼ 10% (ΔHK ∼ 10–12 kOe, HK ∼ 10–11 T) at room temperature. High thermal conductivity heat sink layers, including Ag, Au, Cu, and Cr, are used to optimize the cooling rate and maximize the down- and cross-track thermal gradient, which determines the achievable track density.

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Section: B Fecupt/fe Ecc Mediamentioning

confidence: 99%

“…31 A lot of focus is on doping FePtX with X ¼ Cu to tune the magnetic anisotropy and adjust (lower) the Curie temperature in order to reduce laser power requirements 2,15,32-41 as well as optimizing relevant HAMR media measurements. 42 A typical example is a 100 K T C reduction with about 10 at. % Cu.…”

mentioning

confidence: 99%

Review Article: FePt heat assisted magnetic recording media

Weller¹,

Parker²,

Mosendz³

et al. 2016

Journal of Vacuum Science &Amp; Technology B, Nanotechnology and Microelectronics: Materials, Processing, Measurement, and Phen

159

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“…(002) FWHM of bcc-SL was manipulated by changing the fabrication conditions for CrMn and CrTi whereas the sputtering conditions for MgO and FePt-C was fixed. To promote the L1 0 ordered phase for FePt, the substrate temperature was elevated about 600 o C before deposition of FePt-C film [7,8]. Figure 7 shows the out-of-plane magnetization curve for the L1 0 FePt-C granular films with (002) FWHM of 3.8 (solid), 4.2 (dash), and 13.7 (dot).…”

Section: Magnetic Properties Of Fept-c Granular Films With Highly (00mentioning

confidence: 99%

Amorphous Cr-Ti Texture-inducing Layer Underlying (002) Textured bcc-Cr alloy Seed Layer for FePt-C Based Heat-assisted Magnetic Recording Media

Jeon¹,

Hinata

Saito

2016

Journal of Magnetics

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Cr 100-x Ti x amorphous texture-inducing layers (TIL) were investigated to realize highly (002) oriented L1 0 FePt-C granular films through hetero-epitaxial growth on the (002) textured bcc-Cr 80 Mn 20 seed layer (bcc-SL). Asdeposited TILs showed the amorphous phase in Ti content of 30 ≤ x (at%) ≤ 75. Particularly, films with 40 ≤ x ≤ 60 kept the amorphous phase against the heat treatment over 600 o C. It was found that preference of the crystallographic texture for bcc-SLs is directly affected by the structural phase of TILs. (002) crystallographic texture was realized in bcc-SLs deposited on the amorphous TILs (40 ≤ x ≤ 70), whereas (110) texture was formed in bcc-SLs overlying on crystalline TILs (x < 30 and x > 70). Correlation between the angular distribution of (002) crystal orientation of bcc-SL evaluated by full width at half maximum of (002) It is suggested that the reduction of (002) FWHM affects to the overlying MgO film as well as FePt-C granular film by means of the hetero-epitaxial growth.

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“…This different alignment may explain why there is not a measureable coercivity for the surface biotemplated MNPs when measured in VSM. Hysteresis loops of sputtered CoPt with misaligned grains can show loops with reduced [ 41 ] or no [ 42 ] coercivity depending on the direction in which the external fi eld is applied. As it was only possible to measure the magnetization of the samples in the out-of-plane direction, it may be that the C -axis of the fi lm is aligned in plane, or in some other orientation.…”

Section: Magnetic Properties Of Surface Biotemplated L1 0 Coptmentioning

confidence: 99%

Developing Biotemplated Data Storage: Room Temperature Biomineralization of L1₀CoPt Magnetic Nanoparticles

Galloway

Talbot

Critchley

et al. 2015

Adv Funct Materials

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L10 cobalt platinum can be used to record data at approximately sixfold higher densities than it is possible to on existing hard disks. Currently, fabricating L10 CoPt requires high temperatures (≈500 °C) and expensive equipment. One ecological alternative is to exploit biomolecules that template nanomaterials at ambient temperatures. Here, it is demonstrated that a dual affinity peptide (DAP) can be used to biotemplate L10 CoPt onto a surface at room temperature from an aqueous solution. One part of the peptide nucleates and controls the growth of CoPt nanoparticles from solution, and the other part binds to SiO2. A native silicon oxide surface is functionalized with a high loading of the DAP using microcontact printing. The DAP biotemplates a monolayer of uniformly sized and shaped nanoparticles when immobilized on the silicon surface. X‐ray diffraction shows that the biotemplated nanoparticles have the L10 CoPt crystal structure, and magnetic measurements reveal stable, multiparticle zones of interaction, similar to those seen in perpendicular recording media. This is the first time that the L10 phase of CoPt has been formed without high temperature/vacuum treatment (e.g., annealing or sputtering) and offers a significant advancement toward developing environmentally friendly, biotemplated materials for use in data storage.

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Effect of MgO underlayer misorientation on the texture and magnetic property of FePt–C granular film

Cited by 50 publications

References 35 publications

Review Article: FePt heat assisted magnetic recording media

Review Article: FePt heat assisted magnetic recording media

Amorphous Cr-Ti Texture-inducing Layer Underlying (002) Textured bcc-Cr alloy Seed Layer for FePt-C Based Heat-assisted Magnetic Recording Media

Developing Biotemplated Data Storage: Room Temperature Biomineralization of L1₀CoPt Magnetic Nanoparticles

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Effect of MgO underlayer misorientation on the texture and magnetic property of FePt–C granular film

Cited by 50 publications

References 35 publications

Review Article: FePt heat assisted magnetic recording media

Review Article: FePt heat assisted magnetic recording media

Amorphous Cr-Ti Texture-inducing Layer Underlying (002) Textured bcc-Cr alloy Seed Layer for FePt-C Based Heat-assisted Magnetic Recording Media

Developing Biotemplated Data Storage: Room Temperature Biomineralization of L10CoPt Magnetic Nanoparticles

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Developing Biotemplated Data Storage: Room Temperature Biomineralization of L1₀CoPt Magnetic Nanoparticles