Recording media research for future hard disk drives

Piramanayagam, S. N.; Srinivasan, Kumar

doi:10.1016/j.jmmm.2008.05.007

Cited by 133 publications

(58 citation statements)

References 107 publications

(107 reference statements)

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“…A phenomenological description of thermal activation processes in such systems assumes that the time scales τ of the available relaxation modes depend on the effective energy barriers, δe, emerging from internal interactions and disorder. Their probability distribution, g e (δe), is a characteristic of the system and its optimisation has been central to modern magnetic recording technology [2] and to applications of magnetic nanostructures in biology and medicine [3].…”

Section: Introductionmentioning

confidence: 99%

Consistent energy barrier distributions in magnetic particle chains

Laslett

Ruta

Chantrell

et al. 2016

Physica B: Condensed Matter

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We investigate long-time thermal activation behaviour in magnetic particle chains of variable length. Chains are modelled as Stoner-Wohlfarth particles coupled by dipolar interactions. Thermal activation is described as a hopping process over a multidimensional energy landscape using the discrete orientation model limit of the Landau-Lifshitz-Gilbert dynamics. The underlying master equation is solved by diagonalising the associated transition matrix, which allows the evaluation of distributions of time scales of intrinsic thermal activation modes and their energy representation. It is shown that as a result of the interaction dependence of these distributions, increasing the particle chain length can lead to acceleration or deceleration of the overall relaxation process depending on the initialisation procedure.

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Section: Introductionmentioning

confidence: 99%

Consistent energy barrier distributions in magnetic particle chains

Laslett

Ruta

Chantrell

et al. 2016

Physica B: Condensed Matter

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“…To fulfill the requirements of thermal stability, CoCrPt as well as the [Co/Pt(Pd)] N multilayer system are limited in their extensibility in storage density and thus Fe-Pt alloys in the L1 0 chemically ordered phase are considered as candidate materials for a recording layer in BPM allowing densities beyond 1 Tbit/inch 2 [12]. However, several important aspects have to be considered: (i) Chemical L1 0 ordering is required to induce strong magnetic anisotropy and (ii) (001) texturing of the FePt film is needed to stabilize PMA.…”

Section: Fept Films On Sio 2 Particle Arraysmentioning

confidence: 99%

“…Please note that conventional annealing of FePt films grown on amorphous substrates results in a chemically ordered alloy, but with isotropic orientation of the easy axes of magnetization [67]. Therefore, single crystalline substrates with appropriate orientation like MgO(001) or NaCl(001) can be used to stabilize a (001) texture in FePt alloys via epitaxial growth [12,68]. In this regard, we used [Pt(3 nm)/Cr(50 nm)] seed layers which were deposited at 350°C onto assemblies of nonmagnetic SiO 2 particles to initiate the (001) texture in 5-nm-thick FePt alloy films [39].…”

Section: Fept Films On Sio 2 Particle Arraysmentioning

confidence: 99%

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Magnetic Films on Nanoparticle Arrays

Albrecht¹

2012

TOSURSJ

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Novel properties originating from the combination of magnetism with the reduced dimensionality of nanoobjects are of considerable interest for fundamental science but are also readily used in a wide range of technological applications. To fulfill the demand for larger capacities of storage systems, complex magnetic heterostructures of a nanometer size are envisioned as future magnetic storage media. Here we review recent advances on a novel gradient nanomaterial fabricated by deposition of magnetic thin films onto self-assembled arrays of nonmagnetic spherical particles, resulting in arrays of magnetic caps. Due to the curvature of the particle's surface, magnetic and structural properties of the magnetic thin films differ substantially from their planar counterparts with respect to the equilibrium magnetic domain pattern as well as magnetization reversal behavior. It will be shown that varying the size of the particles as well as the thickness of the deposited layers, the magnetostatic and exchange coupling between the neighboring caps can be systematically modified, providing direct access to the change of fundamental magnetic interactions at the nanoscale. Furthermore, these magnetic cap structures were employed to realize so called bit patterned magnetic media, which is one of the most promising concepts in magnetic data storage to provide areal densities beyond 1 Tbit/inch 2 . In this respect, important aspects regarding the potential application of the magnetic cap structures in magnetic data storage will be addressed.

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“…Since the middle of the 1970s, when Iwasaki et al proposed perpendicular magnetic recording as an alternative to conventional longitudinal magnetic recording [1][2][3], thin films with out-of-plane magnetic anisotropy have been widely studied for recording media applications [4][5][6][7] as well as for patterned magnetic media [8][9][10][11]. Magnetic films with perpendicular magnetic anisotropy (PMA) patterned into stripes and lines [12][13][14][15] have been also proposed for nanoscale spintronic devices such as those based on current-driven domain-wall motion [16,17].…”

Section: Introductionmentioning

confidence: 99%

Microscopic reversal magnetization mechanisms in CoCrPt thin films with perpendicular magnetic anisotropy: Fractal structure versus labyrinth stripe domains

et al. 2017

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The magnetization reversal of CoCrPt thin films has been examined as a function of thickness using magnetooptical Kerr effect (MOKE) microscopy and first-order reversal curves (FORC) techniques. MOKE images show differentiated magnetization reversal regimes for different film thicknesses: while the magnetic domains in 10-nm-thick CoCrPt film resemble a fractal structure, a labyrinth stripe domain configuration is observed for 20-nm-thick films. Although FORC distributions for both cases show two main features related to irreversible processes (propagation and annihilation fields) separated by a mostly flat region, this method can nonetheless distinguish which magnetization reversal process is active according to the horizontal profile of the first FORC peak, or propagation field. A single-peak FORC profile corresponds to the fractal magnetization reversal, whereas a flat-peak FORC profile corresponds to the labyrinth magnetization reversal.

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Recording media research for future hard disk drives

Cited by 133 publications

References 107 publications

Consistent energy barrier distributions in magnetic particle chains

Consistent energy barrier distributions in magnetic particle chains

Magnetic Films on Nanoparticle Arrays

Microscopic reversal magnetization mechanisms in CoCrPt thin films with perpendicular magnetic anisotropy: Fractal structure versus labyrinth stripe domains

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