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           FePt-oxide columnar perpendicular media with high coercivity and small grain size

Yang, En‐Che; Laughlin, David E.

doi:10.1063/1.2956691

Cited by 76 publications

(22 citation statements)

References 11 publications

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“…Although good surface roughness and columnar structure have been reported with a SiO 2 segregant, 32 planer particle separation is poor. These results suggest that the separating tendency of SiO 2 is too weak compared to that for carbon.…”

Section: Exploration Of a New Fept-x Systemmentioning

confidence: 99%

Microstructure Control of L10-Ordered FePt Granular Film for Heat-Assisted Magnetic Recording (HAMR) Media

Varaprasad

Takahashi

Hono

2013

JOM

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Section: Exploration Of a New Fept-x Systemmentioning

confidence: 99%

Microstructure Control of L10-Ordered FePt Granular Film for Heat-Assisted Magnetic Recording (HAMR) Media

Varaprasad

Takahashi

Hono

2013

JOM

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“…Addtion of C leads to a grain size reduction [2], an improvement of main diameter distribution, which is very important in S/N ratio maximization, and to the isolation of the magnetic particles [3,4]. With the addition of SiO 2 better control of the coercivity is achieved, a columnar shape is realised with cuboid-like particles which are considered more suitable for the magnetic recording [5]. .…”

Section: Introductionmentioning

confidence: 99%

Study of microstructure and magnetic properties of L1₀FePt/SiO₂thin films

Γιαννόπουλος

Speliotis

Niarchos

2014

EPJ Web of Conferences

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Abstract.Achieving magnetic recording densities in excess of 1Tbit/in 2 requires not only perpendicular media with anisotropies larger than 7 MJ/m 3 , making FePt alloys an ideal choice, but also a narrow distribution below 10 nm for a reduced S/N ratio. Such grain size reduction and shape control are crucial parameters for high density magnetic recording, along with high thermal stability. Previous work has shown that the L1 0 FePt grain size can be controlled by alloying FePt with materials such as C, Ag, and insulators such as AlO x , MgO. Au and Al 2 O 3 also act to segregate and magnetically decouple the FePt grains. Better results were obtained with C with respect to the uniformity of grains and SiO 2 with respect to the shape. We present our results on co-sputtering FePt with C or SiO 2 (up to 30 vol % ) on MgO (001) single crystal substrates at 350 and 500 o C.With C or SiO 2 addition we achieved grain size reduction, shape control and isolated structure formation, producing continuous films with high uniformity and a narrow grain size distribution. These additions thus allow us to simultaneously control the coercivity and the S/N ratio. We also will report structural and microstructural properties.

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“…[1][2][3][4] For achieving high density, the film media needs to be granular in nature, of small and uniform sized grains with a nonmagnetic phase at the grain boundaries. [5][6][7] Well defined carbon regions at the grain boundaries with small magnetic grain sizes have been achieved in FePt(L1 0 )-C films. However, non-columnar film microstructures in these films leads to a layer with new secondary grains, leading to undesired magnetic properties.…”

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confidence: 99%

Columnar grain growth of FePt(L1) thin films

Yang

Laughlin

et al. 2012

Journal of Applied Physics

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An experimental approach for obtaining perpendicular FePt-SiOx thin films with a large height to diameter ratio FePt(L1 0 ) columnar grains is presented in this work. The microstructure for FePt-SiOx composite thin films as a function of oxide volume fraction, substrate temperature, and film thickness is studied by plan view and cross section TEM. The relations between processing, microstructure, epitaxial texture, and magnetic properties are discussed. By tuning the thickness of the magnetic layer and the volume fraction of oxide in the film at a sputtering temperature of 410 C, a 16 nm thick perpendicular FePt film with $8 nm diameter of FePt grains was obtained. The height to diameter ratio of the FePt grains was as large as 2. Ordering at lower temperature can be achieved by introducing a Ag sacrificial layer. FePt(L1 0 ) is considered to be one of the most promising materials for ultrahigh density recording applications. [1][2][3][4] For achieving high density, the film media needs to be granular in nature, of small and uniform sized grains with a nonmagnetic phase at the grain boundaries. [5][6][7] Well defined carbon regions at the grain boundaries with small magnetic grain sizes have been achieved in FePt(L1 0 )-C films. However, non-columnar film microstructures in these films leads to a layer with new secondary grains, leading to undesired magnetic properties. 8 The difficulty in obtaining columnar growth of L1 0 FePt grains with large height to diameter ratios lies in perhaps the high surface energy associated with the material choice.In this work, an experimental method for obtaining perpendicular FePt-SiOx thin films with large height to diameter ratio FePt(L1 0 ) columnar grains is presented. It was found that the microstructure of composite films can be influenced by not only the deposition pressure, temperature, and oxide volume fractions, but also the choice of matrix material and thickness of the thin film.FePt/oxide multilayers and MgO/Ta underlayers were deposited on Si substrates by RF sputtering. The base pressure was approximately 5 Â 10 À7 Torr and the argon pressure during deposition was maintained at 10 mTorr. The MgO/Ta underlayers were deposited at room temperature; the FePt/ oxide multilayers were fabricated by the alternating sputtering of the Fe 55 Pt 45 alloy and the SiOx targets on a heated substrate. The substrate temperature was varied between 370 C to 475 C during the multilayer deposition. X-ray diffraction and transmission electron microscopy were used to study the texture and microstructure of the films. An alternating gradient force magnetometer (AGFM) and a polar magneto-optical Kerr effect looper (MOKE) were used to investigate the magnetic properties.The cross section TEM images in Fig. 1 show the microstructure of FePt-SiOx composite films as a function of oxide volume fraction (OVF). For this set of samples, the FePt/ SiOx multilayers deposition temperature was maintained at 410 C and the FePt film thickness was fixed at 16 nm. As shown in the figure, in the low OVF f...

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L 1 FePt-oxide columnar perpendicular media with high coercivity and small grain size

Cited by 76 publications

References 11 publications

Microstructure Control of L10-Ordered FePt Granular Film for Heat-Assisted Magnetic Recording (HAMR) Media

Microstructure Control of L10-Ordered FePt Granular Film for Heat-Assisted Magnetic Recording (HAMR) Media

Study of microstructure and magnetic properties of L1₀FePt/SiO₂thin films

Columnar grain growth of FePt(L1) thin films

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L 1 FePt-oxide columnar perpendicular media with high coercivity and small grain size

Cited by 76 publications

References 11 publications

Microstructure Control of L10-Ordered FePt Granular Film for Heat-Assisted Magnetic Recording (HAMR) Media

Microstructure Control of L10-Ordered FePt Granular Film for Heat-Assisted Magnetic Recording (HAMR) Media

Study of microstructure and magnetic properties of L10FePt/SiO2thin films

Columnar grain growth of FePt(L1) thin films

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Study of microstructure and magnetic properties of L1₀FePt/SiO₂thin films