Effect of damping constant on the switching limit of a thin-film recording head

Mao, Chris Y.; Zhu, Jian‐Gang; White, Robert M.; Min, Tai

doi:10.1063/1.369944

Cited by 18 publications

(5 citation statements)

References 5 publications

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“…The damping constant is a material parameter that has a significant effect on the magnetization reversal process as well as switching time. In general, it has two influences: firstly, it reduces the magnetization-precession time and thus, after cross the energy barrier, accelerates to reach the ground/stable state 47,48 . Secondly, damping hinders energy absorption during climbing the energy barrier for magnetization reversal 49 .…”

Section: Numerical Resultsmentioning

confidence: 99%

Shape anisotropy effect on magnetization reversal induced by linear down chirp pulse

Juthy,

Pikul,

Akanda

et al. 2021

Preprint

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We investigate the influence of shape anisotropy on the magnetization reversal of a single-domain magnetic nanoparticle driven by a circularly polarized linear down-chirp microwave field pulse (DCMWP). Based on the Landau-Lifshitz-Gilbert equation, numerical results show that the three controlling parameters of DCMWP, namely, microwave amplitude, initial frequency and chirp rate, decrease with the increase of shape anisotropy. These findings are related to the effective anisotropy and thus to the height energy barrier which separates the two stable states. The result of damping dependence of magnetization reversal indicates that for a certain sample shape, there exists an optimal damping situation at which magnetization is fastest. Moreover, it is also shown that the required microwave field amplitude can be lowered by applying the spin-polarized current simultaneously. The usage of an optimum combination of both microwave field pulse and current is suggested to achieve cost efficiency and faster switching. So these findings may provide the knowledge to fabricate the shape of a single domain nanoparticle for the fast and power-efficient magnetic data storage device.

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Section: Numerical Resultsmentioning

confidence: 99%

Shape anisotropy effect on magnetization reversal induced by linear down chirp pulse

Juthy,

Pikul,

Akanda

et al. 2021

Preprint

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“…where A is the exchange constant and V = τ L y L z is the film volume. To obtain (13) we have used the following formula: (14) where ∆(•) is the Kronecker delta function: ∆(q) = 1, if q = 0 and ∆(q) = 0 otherwise.…”

Section: A Magnetic Energymentioning

confidence: 99%

“…The problem of nonlinear spin-wave excitation during reversal has been explored by numerical simulations in nanograins [12], [13], and thin films [14], [15]. All these simulations have been performed using conventional local micromagnetic modeling, which includes: a) the analysis of intra-and inter-cell interactions, b) analysis of phenomenological dynamic equations, and c) computer simulations.…”

Section: Introductionmentioning

confidence: 99%

Microscopic mechanisms of magnetization reversal (invited)

Safonov

2004

Journal of Applied Physics

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Two principal scenarios of magnetization reversal are considered. In the first scenario all spins perform coherent motion and an excess of magnetic energy directly goes to a nonmagnetic thermal bath. A general dynamic equation is derived which includes a tensor damping term similar to the Bloch-Bloembergen form but the magnetization magnitude remains constant for any deviation from equilibrium. In the second reversal scenario, the absolute value of the averaged sample magnetization is decreased by a rapid excitation of nonlinear spin-wave resonances by uniform magnetization precession. We have developed an analytic k-space micromagnetic approach that describes this entire reversal process in an ultrathin soft ferromagnetic film for up to 90 o deviation from equilibrium. Conditions for the occurrence of the two scenarios are discussed.

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“…The out-of-plane demagnetization field is proportional to the saturation magnetization of the yoke. Therefore, the higher the yoke saturation magnetization, the faster the magnetization of the yoke rotates and the faster the flux rise time [5].…”

Section: B Single-turn Design With Closed-edge Laminationmentioning

confidence: 99%

Understanding single-turn write head design at narrow track widths

Zhu

Mao²,

White

et al. 2002

IEEE Trans. Magn.

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This paper provides a systematic micromagnetic analysis on the magnetization processes in various miniaturized single-turn head designs. The calculation results show that a thick yoke yields the formation of a magnetization vortex through the yoke thickness, resulting in efficient flux conduction at small yoke dimensions. A vortex structure is also important for the pole tips to maintain zero remanence after writing. Following this understanding, a hollow yoke structure has been studied to promote the efficient flux conduction in the yoke and flux closure mode in the pole tips at the remanent state. The simulation results are elucidating for efficient single-turn head designs at small yoke dimensions.Index Terms-Narrow tracks, single-turn write heads, thin film heads, write heads.

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Effect of damping constant on the switching limit of a thin-film recording head

Cited by 18 publications

References 5 publications

Shape anisotropy effect on magnetization reversal induced by linear down chirp pulse

Shape anisotropy effect on magnetization reversal induced by linear down chirp pulse

Microscopic mechanisms of magnetization reversal (invited)

Understanding single-turn write head design at narrow track widths

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