{
  "status": "research",
  "advantages": [],
  "limitations": [],
  "supersedes": [],
  "supersededBy": [],
  "firstSeen": null,
  "lastSeen": null,
  "updated": "2026-10-16",
  "slug": "hamr-thermal-gradient",
  "term": "HAMR thermal gradient",
  "aliases": [
    "HAMR temperature gradient"
  ],
  "definition": "A HAMR thermal gradient is the spatial rate of temperature change in the recording medium along a specified direction.",
  "note": "A gradient in K/nm is not a cooling rate in K/s; location, direction and the moving heat profile matter [hosen-gradient-2023]. A sharper profile does not by itself guarantee successful switching: pulse duration and field also matter, as illustrated by isolated-grain simulations with spatially uniform heating [meo-multiscale-2020]. Those simulations test temporal dynamics, not a measured full-track spatial-gradient optimization.",
  "citations": [
    {
      "id": "hosen-gradient-2023",
      "title": "Hosen and Victora: Impact of Curie Temperature Distribution and Anisotropy Field Distribution on the User Density of HAMR Under Different Thermal Gradients, IEEE Transactions on Magnetics 59(11), 3201005 (2023), doi:10.1109/TMAG.2023.3287829; institutional abstract only",
      "url": "https://experts.umn.edu/en/publications/impact-of-curie-temperature-distribution-and-anisotropy-field-dis",
      "accessed": "2026-10-16"
    },
    {
      "id": "meo-multiscale-2020",
      "title": "Meo et al.: Magnetisation dynamics of granular HAMR media by means of a multiscale model, arXiv:2004.13345v1 (2020); sections II.2 and III.2, Figures 2-4",
      "url": "https://arxiv.org/html/2004.13345v1",
      "accessed": "2026-10-16"
    }
  ],
  "related": [
    "hamr",
    "curie-temperature-distribution",
    "transition-jitter"
  ]
}