Experimental estimates of in-plane thermal conductivity in FePt-C granular thin film heat assisted magnetic recording media using a model layered system

Ho, Hoan; Sharma, Abhishek; Ong, Wee‐Liat; Malen, Jonathan A.; Bain, J.A.; Zhu, Jian‐Gang

doi:10.1063/1.4821950

Cited by 15 publications

(9 citation statements)

References 25 publications

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“…As for the granular FePt medium, which consisted of columnar FePt grains segregated by thin C grain boundaries, the in-plane thermal conductivity was below 1 W mK −1 , and the vertical thermal conductivity could be over 10 times the in-plane one, as reported in Ref. 4. As shown in Table I, the in-plane thermal conductivity of the recording layer was fixed at 1 W mK −1 , and the vertical thermal conductivity was changed from 1 to 24 W mK −1 .…”

Section: (A)supporting

confidence: 60%

Relationship between temperature rise and thermal conductivity in a magnetic medium during heated dot magnetic recording

Akagi

Matsushima

2022

Jpn. J. Appl. Phys.

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In this study, we investigated the relationship between the temperature rise in the recording dots of a bit-patterned medium and its thermal conductivity during heated dot magnetic recording (HDMR) using numerical calculation (electromagnetic field and heat conduction analyses). When the thermal conductivities of the recording and heat sink layers were anisotropic, the temperature rise of a dot’s lower cell could be increased while maintaining a small temperature difference between the upper and lower cells. The HDMR process was calculated via micromagnetic simulation using the Landau–Lifshitz–Bloch equation at vertical and in-plane thermal conductivities of 24.0 and 1.0 W/mK (12.0 and 10.0 W/mK), respectively, for the recording (heat sink) layer. Results showed a bit error rate of 0%, and there was no error.

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Section: (A)supporting

confidence: 60%

Relationship between temperature rise and thermal conductivity in a magnetic medium during heated dot magnetic recording

Akagi

Matsushima

2022

Jpn. J. Appl. Phys.

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“…Our measurement of κ = 8.8 ± 0.6 W m −1 K −1 for the A1 phase at room temperature is consistent with the measurement of an A1 disordered FePt thin film ( κ = 8.5 W m −1 K −1 ) in ref. 10 , where they have used the frequency domain thermoreflectance technique to measure the thermal conductivity. However, our measurement of κ = 11.5 ± 0.8 W m −1 K −1 for the L1 0 phase is slightly lower than that reported in ref.…”

Section: Thermal Conductivitymentioning

confidence: 99%

Influence of chemical ordering on the thermal conductivity and electronic relaxation in FePt thin films in heat assisted magnetic recording applications

Giri

Wee

Jain

et al. 2016

Sci Rep

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We report on the out-of-plane thermal conductivities of tetragonal L10 FePt (001) easy-axis and cubic A1 FePt thin films via time-domain thermoreflectance over a temperature range from 133 K to 500 K. The out-of-plane thermal conductivity of the chemically ordered L10 phase with alternating Fe and Pt layers is ~23% greater than the thermal conductivity of the disordered A1 phase at room temperature and below. However, as temperature is increased above room temperature, the thermal conductivities of the two phases begin to converge. Molecular dynamics simulations on model FePt structures support our experimental findings and help shed more light into the relative vibrational thermal transport properties of the L10 and A1 phases. Furthermore, unlike the varying temperature trends in the thermal conductivities of the two phases, the electronic scattering rates in the out-of-plane direction of the two phases are similar for the temperature range studied in this work.

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“…One of the possible causes for the grain-to-grain heating variation is grain boundary thickness distribution in the media. Recent experimental studies on modeled FePt-C multilayer film suggests that the thermal resistance of carbon layer sandwiched in between two FePt layers arises from both FePt-C interfaces and the bulk of carbon layer itself [12], [13]. For 1 nm thick carbon layer, 40% of the thermal resistance can be due to the two interfaces.…”

Section: Effect Of Grain Boundary Thickness Distributionmentioning

confidence: 99%

SNR Impact of Noise by Different Origins in FePt-<inline-formula> <tex-math notation="LaTeX">$\text{L}1_{\boldsymbol 0}$ </tex-math></inline-formula> HAMR Media

Zhu

2015

IEEE Trans. Magn.

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In this paper, we present a micromagnetic analysis on two key noise mechanisms for current FePt-L10-based heat-assisted magnetic recording (HAMR) media: grain-to-grain variations of anisotropy field and Curie temperature. We found that the signal-to-noise ratio (SNR) versus heating power measurement could be used to distinguish the noise arising from these two different origins. We also found that in today's HAMR media, the dominate noise origin is likely to be the combination of Curie temperature distribution and heating, or temperature, variation from grain to grain. As one of the possible mechanisms for grain-to-grain heating variation, the effect of grain boundary thickness distribution is studied in terms of its impact to recording SNR. It is concluded that reducing the combined heating and Curie temperature distribution is critical for the realization of the area density capability gain promised by the technology.Index Terms-Curie temperature, heat-assisted magnetic recording (HAMR), micromagnetic modeling, perpendicular magnetic recording (PMR).

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Experimental estimates of in-plane thermal conductivity in FePt-C granular thin film heat assisted magnetic recording media using a model layered system

Cited by 15 publications

References 25 publications

Relationship between temperature rise and thermal conductivity in a magnetic medium during heated dot magnetic recording

Relationship between temperature rise and thermal conductivity in a magnetic medium during heated dot magnetic recording

Influence of chemical ordering on the thermal conductivity and electronic relaxation in FePt thin films in heat assisted magnetic recording applications

SNR Impact of Noise by Different Origins in FePt-<inline-formula> <tex-math notation="LaTeX">$\text{L}1_{\boldsymbol 0}$ </tex-math></inline-formula> HAMR Media

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