Dependence of thermal decay on the magnetic cluster size of perpendicular magnetic recording media

Miyashita, Eiichi; Funabashi, Nobuhiko; Taguchi, Ryo; Tamaki, Toru; Nakamura, Shoichi

doi:10.1016/j.jmmm.2004.10.014

Cited by 11 publications

(4 citation statements)

References 5 publications

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“…The slopes of the perpendicular loops at coercivity remained very steep and showed no obvious change with C concentration. These results indicated that exchange coupling did not decrease even for the well-isolated FePt grains with 20 vol% C concentration [18][19][20].…”

Section: Resultsmentioning

confidence: 82%

Microstructural and magnetic properties of L1₀FePt–C (0 0 1) textured nanocomposite films grown on different intermediate layers

Chen

Lim

et al. 2008

J. Phys. D: Appl. Phys.

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The FePt : C films with different volume fractions of carbon and different thicknesses were epitaxially grown on a CrRu(2 0 0) underlayer with Pt and MgO intermediate layers. The magnetic properties and microstructure of these FePt : C films were investigated. The FePt : C films grown on the Pt intermediate layer consisted of a continuous layer of FePt, with overlying granular FePt grains, while the FePt : C films grown on the MgO intermediate layer consisted of granular FePt : C layers with overlying granular grains. The formation of the overlying granular FePt grains was attributed to carbon diffusion to the surface which resulted in the second nucleation of FePt. The different interface energies and surface energies of FePt on Pt and MgO intermediate layers caused the formation of an initial continuous FePt layer on the Pt intermediate layer and initial granular FePt layers on the MgO intermediate layer. The coupling between the continuous FePt layer or the granular FePt layer and the overlying granular FePt grains resulted in simultaneous magnetization reversal and thus strong exchange coupling in FePt : C films.

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Section: Resultsmentioning

confidence: 82%

Microstructural and magnetic properties of L1₀FePt–C (0 0 1) textured nanocomposite films grown on different intermediate layers

Chen

Lim

et al. 2008

J. Phys. D: Appl. Phys.

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“…6,26 Even if the intergrain exchange coupling is zero on average, the dispersion of exchange coupling still causes magnetic clusters. 27 The magnetic cluster size expected for 2.0ϫ 10 −7 erg/ cm is calculated to be about 10 nm, 27 which is far smaller than the cluster size actually observed ͑40-50 nm͒. 27 The magnetic cluster size expected for 2.0ϫ 10 −7 erg/ cm is calculated to be about 10 nm, 27 which is far smaller than the cluster size actually observed ͑40-50 nm͒.…”

Section: Intergrain Exchange Coupling and Its Effect On The Magnetmentioning

confidence: 91%

Magnetic reversal field map combined with medium noise analysis in CoCrPt–SiO2 granular perpendicular recording medium

Ishio

Wasiya

Saito

et al. 2006

Journal of Applied Physics

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Reverse dc erase medium noise analysis on exchange-coupling effect in coupled granular/continuous perpendicular recording media J. Appl. Phys. 93, 7855 (2003); 10.1063/1.1557757 Effects of intermediate layers on magnetic properties and read/write performance in CoCrPt perpendicular recording media with an FeHfN soft magnetic underlayerThe spatial distribution of the magnetic reversal field ͑MRF͒ in a CoCrPt-SiO 2 granular perpendicular recording medium was measured with in-field magnetic force microscopy and combined with the recorded pattern and the medium noise observed at the same location. The areas having low MRF tend to make reverse domains at bit or zigzag transition boundaries, while regions with high MRF do not correlate well with medium noise. The MRF map measured at 20 Oe intervals shows that magnetic reversal occurs mainly in regions adjacent to an already reversed area, suggesting the existence of moderate intergrain exchange couplings. It is concluded that control of the spatial fluctuation of physical parameters such as intergrain exchange interactions, the anisotropy field, grain size, and chemical composition is essential to reduce the medium noise.

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“…The high anisotropy values of these CoPt phases [ 15 , 16 ] allow for the stabilization of their magnetization against thermal fluctuations and demagnetizing effects at very low dimensions [ 17 , 18 , 19 , 20 , 21 ], properties which are fundamental for application in permanent magnets and recording media [ 22 , 23 , 24 , 25 ]. Additionally, their chemical stability in alkaline and acidic environments makes them excellent candidates for low-platinum-content electrocatalysts [ 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 ].…”

Section: Introductionmentioning

confidence: 99%

Low-Platinum-Content Exchange-Coupled CoPt Nanoalloys with Enhanced Magnetic Properties

Basina,

Alexandrakis,

Panagiotopoulos

et al. 2024

Nanomaterials

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Bimetallic colloidal CoPt nanoalloys with low platinum content were successfully synthesized following a modified polyol approach. Powder X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), and transmission electron microscopy (TEM) studies were performed to estimate the crystal structure, morphology, and surface functionalization of the colloids, respectively, while the room-temperature magnetic properties were measured using a vibrating sample magnetometer (VSM). The particles exhibit excellent uniformity, with a narrow size distribution, and display strong room-temperature hysteretic ferromagnetic behavior even in the as-made form. Upon annealing at elevated temperatures, progressive formation and co-existence of exchange coupled, of both chemically ordered and disordered phases significantly enhanced the room-temperature coercivity.

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Dependence of thermal decay on the magnetic cluster size of perpendicular magnetic recording media

Cited by 11 publications

References 5 publications

Microstructural and magnetic properties of L1₀FePt–C (0 0 1) textured nanocomposite films grown on different intermediate layers

Microstructural and magnetic properties of L1₀FePt–C (0 0 1) textured nanocomposite films grown on different intermediate layers

Magnetic reversal field map combined with medium noise analysis in CoCrPt–SiO2 granular perpendicular recording medium

Low-Platinum-Content Exchange-Coupled CoPt Nanoalloys with Enhanced Magnetic Properties

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Dependence of thermal decay on the magnetic cluster size of perpendicular magnetic recording media

Cited by 11 publications

References 5 publications

Microstructural and magnetic properties of L10FePt–C (0 0 1) textured nanocomposite films grown on different intermediate layers

Microstructural and magnetic properties of L10FePt–C (0 0 1) textured nanocomposite films grown on different intermediate layers

Magnetic reversal field map combined with medium noise analysis in CoCrPt–SiO2 granular perpendicular recording medium

Low-Platinum-Content Exchange-Coupled CoPt Nanoalloys with Enhanced Magnetic Properties

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Product

Resources

About

Microstructural and magnetic properties of L1₀FePt–C (0 0 1) textured nanocomposite films grown on different intermediate layers

Microstructural and magnetic properties of L1₀FePt–C (0 0 1) textured nanocomposite films grown on different intermediate layers