{
  "slug": "fc-mamr",
  "term": "Flux-control microwave-assisted magnetic recording (FC-MAMR)",
  "aliases": [
    "FC-MAMR",
    "Flux Control MAMR"
  ],
  "definition": "Flux-control microwave-assisted magnetic recording (FC-MAMR) is Toshiba's HDD write-assist technique that uses a spintronic device between the write poles to redirect magnetic flux toward the recording medium and strengthen the write field.",
  "note": "Toshiba's 2021 account places the device between the main and auxiliary poles; flux control avoids requiring media designed for microwave resonance [toshiba-fc-mamr-2021]. This identifies the assist mechanism, not an absence of all oscillation in the device. Toshiba's 2021 MG09 technical article distinguishes its commercial FC-MAMR implementation from MAS-MAMR's microwave-assisted media switching [toshiba-mg09-2021]. The MG09 design also uses per-head STO voltage control and applies the bias only during writing to limit device degradation [toshiba-fc-bias-2021]; this does not quantify fleet reliability.",
  "status": "shipping",
  "advantages": [],
  "limitations": [
    "A product's MAMR label does not by itself establish that it uses microwave-assisted media switching."
  ],
  "related": [
    "mamr",
    "mas-mamr",
    "epmr",
    "pmr"
  ],
  "supersedes": [],
  "supersededBy": [],
  "firstSeen": null,
  "lastSeen": null,
  "citations": [
    {
      "id": "toshiba-fc-mamr-2021",
      "title": "Toshiba: Science and Technology Highlights 2021, section 1.12, p. 15",
      "url": "https://www.global.toshiba/content/dam/toshiba/ww/technology/corporate/review/2021/toshiba-review-science-and-technology-highlights-2021/2101.pdf#page=15",
      "accessed": "2026-10-16"
    },
    {
      "id": "toshiba-mg09-2021",
      "title": "Toshiba: High-Reliability FC-MAMR Nearline HDD with a Capacity of 18 TB (2021), pp. 1-2",
      "url": "https://toshiba.semicon-storage.com/content/dam/toshiba-ss-v3/master/en/storage/product/data-center-enterprise/202102025_nearlineHDD_18TB_e.pdf",
      "accessed": "2026-10-16"
    },
    {
      "id": "toshiba-fc-bias-2021",
      "title": "Takeo and Sugiyama: Toshiba Review 76(6), pp. 7-10 (2021), section 5, p. 10: STO degradation prevention (Japanese)",
      "url": "https://www.global.toshiba/content/dam/toshiba/jp/technology/corporate/review/2021/06/a03.pdf#page=4",
      "accessed": "2026-10-16"
    }
  ],
  "updated": "2026-10-16"
}