Micromagnetic modeling for heat-assisted magnetic recording

Li, Zhenghua; Wei, Dan; Wei, Fulin

doi:10.1016/j.jmmm.2008.08.085

Cited by 11 publications

(8 citation statements)

References 6 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…8 Grain-level micromagnetic simulations based on the LLG equations have also been performed which account for the thermalfluctuation induced reduction in the intrinsic grain moment and uniaxial anisotropy (K) through the introduction of temperature dependent profiles for M(T) and K(T) into the simulation. [9][10][11] The results of these studies illustrate the utility of the thermal EAMR idea by integrating these concepts into a model of the recording process. A more sophisticated approach to account for the spin structure internal to grains at elevated temperatures through the introduction of longitudinal degrees of freedom within the general framework of micromagnetics (called the LLB (Landau-Lifshitz-Bloch) method) has also been examined.…”

mentioning

confidence: 77%

“…The present results are compared with the above-mentioned appoach which integrate M (T ) and K(T ) profiles into the LLG equations. 9,10 Solutions to the standard LLG equation with the stochastic thermal field were obtained using the Euler integration method with damping constant α = 0.1, a time step of 0.001 ps, and with rotations updated using a quaternions representation. 14 Magnetic parameters were based on generic single-layer FePt-type media with a saturation moment M s = 1000 emu/cc, inter-grain exchange was omitted and uniaxial anisotropy was K = 5 × 10 7 erg/cc, giving H K = 100 kOe.…”

mentioning

confidence: 99%

See 1 more Smart Citation

Atomic level micromagnetic model of recording media switching at elevated temperatures

Mercer¹,

Plumer²,

Whitehead³

et al. 2011

Applied Physics Letters

View full text Add to dashboard Cite

An atomic level micromagnetic model of granular recording media is developed and applied to examine external field-induced grain switching at elevated temperatures which captures non-uniform reversal modes. The results are compared with traditional methods which employ the Landau-Lifshitz-Gilbert equations based on uniformly magnetized grains with assigned intrinsic temperature profiles for M (T ) and K(T ). Using nominal parameters corresponding to high-anisotropy FePt-type media envisioned for Energy Assisted Magnetic Recording, our results demonstrate that atomic-level reversal slightly reduces the field required to switch grains at elevated temperatures, but results in larger fluctuations, when compared to a uniformly magnetized grain model.

show abstract

mentioning

confidence: 77%

mentioning

confidence: 99%

Atomic level micromagnetic model of recording media switching at elevated temperatures

Mercer¹,

Plumer²,

Whitehead³

et al. 2011

Applied Physics Letters

View full text Add to dashboard Cite

show abstract

“…19 The differential equations of thermal diffusion are solved numerically based on the assumption that the specific heat capacity of the recording layer is constant 19,20 and do not consider modulations arising from local temperature variations and the granular structure of the medium.…”

Section: Introductionmentioning

confidence: 99%

Finite size effects in L1o-FePt nanoparticles

Lyberatos

Weller

Parker

2013

Journal of Applied Physics

View full text Add to dashboard Cite

Finite size effects on the temperature dependence of the uniaxial magnetic anisotropy, longitudinal and transverse susceptibilities and specific heat are examined for L1 o -ordered FePt nanoparticles using an atomistic model based on an effective classical spin Hamiltonian. At low temperatures below criticality, we study the intrinsic uniaxial magnetic anisotropy energy (MAE) K 1 and its scaling with magnetization K 1 ðTÞ $ M s ðTÞ d and using Langevin dynamics simulations we show that the dependence of the exponent d on the size L and aspect ratio of the grain arises from decomposition of the MAE into bulk and surface dependent terms. Monte Carlo simulations in the critical regime near the Curie temperature T c , show that the temperature variation of the specific heat and longitudinal susceptibility is given by finite size scaling relations c ¼ L a=c ðL 1= Þ and v ¼ L c=ṽ ðL 1= Þ, respectively, where ¼ ðT À T c Þ=T c is the reduced temperature, and the susceptibility scaling functionṽ can be approximated by a Lorentzian. Our estimates of the critical exponents a; c, and appear to be in agreement with the universality class of the 3D Ising model. V C 2013 AIP Publishing LLC. [http://dx.

show abstract

“…When the magnetic write field (H w ) from the recording head surpasses the reduced coercivity, the write track is written in the recording region of the thermal spot in the medium. [19][20][21] The written track width is based mostly on the thermal spot and the sharp increase in coercivity as the temperature falls across cross-track positions. The heating power that causes H K decreases is regulated by the laser operating current above the lasing threshold ( ) I op of a laser diode used to excite the NFT.…”

Section: Introductionmentioning

confidence: 99%

Track width measurement in heat-assisted magnetic recording systems using the cross-track DC noise method

Kampun¹,

Lekawat²,

Tongsomporn³

2022

Jpn. J. Appl. Phys.

View full text Add to dashboard Cite

This paper uses a cross-track DC noise measurement technique to determine the written track width in heat-assisted magnetic recording (HAMR). The method is approached as a simple, no-extra-hardware-required technique on a spin-stand to determine the written track width as well as the DC noise amplitude at the center track in a HAMR system. The track width data show the expected trends with changing laser operating current (I_op) and write current (I_w), and they are strongly correlated with track density (TD) capabilities and physical near-field transducer (NFT) Peg width. The written track width is essentially defined by the I_op, which increases as I_op increases. The method is useful for comparing the magnetic responses of different writer pole or NFT Peg geometries, as well as media design comparison to provide insight into the head/component necessary to improve HAMR system performance, which is useful HAMR recording parameters for head/media designers and test engineers.

show abstract

Micromagnetic modeling for heat-assisted magnetic recording

Cited by 11 publications

References 6 publications

Atomic level micromagnetic model of recording media switching at elevated temperatures

Atomic level micromagnetic model of recording media switching at elevated temperatures

Finite size effects in L1o-FePt nanoparticles

Track width measurement in heat-assisted magnetic recording systems using the cross-track DC noise method

Contact Info

Product

Resources

About