Optical Analysis of HAMR Media

R. H. Victora, Ali Ghoreyshi

Research output: Contribution to journalArticlepeer-review

5 Scopus citations


We have studied the impact of structural randomness on the variation in optical absorption of recording grains. Using finite-difference time-domain simulation, we demonstrate that randomness in size, shape, and position of FePt grain can cause 2%-9% variation in absorption, depending on the strength of randomness. We have also discussed the resulting impact of several design parameters: air gap, average grain size and its standard deviation, size, and permittivity of grain boundaries, seedlayer thickness, and aspect ratio of recording grains. We demonstrate that the impact of random absorption on jitter is comparable to experimentally estimated variations in Curie temperature {\sigma }-{T-{c}}. In the case of standard recording system parameters, we observe {\sigma }-{T}\sim 1.5 % averaged over the write bubble which corresponds to {\sigma }-{T}\sim 3 % for the grains inside.

Original languageEnglish (US)
Article number8480864
JournalIEEE Transactions on Magnetics
Issue number3
StatePublished - Mar 2019

Bibliographical note

Funding Information:
This work was supported by ASTC/IDEMA. The authors would like to thank the Minnesota Supercomputing Institute, University of Minnesota, Minneapolis, MN, USA, for providing resources that contributed to the research results reported within this paper.

Publisher Copyright:
© 1965-2012 IEEE.


  • Effective medium theory (EMT)
  • heat-assisted magnetic recording (HAMR)
  • jitter
  • optical absorption


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