{
  "slug": "mas-mamr",
  "term": "Microwave-assisted switching MAMR (MAS-MAMR)",
  "aliases": [
    "MAS-MAMR",
    "Microwave Assisted Switching MAMR"
  ],
  "definition": "Microwave-assisted switching MAMR (MAS-MAMR) is a recording technique in which a spin-torque oscillator adds a microwave magnetic field to the write field, reducing the field needed to reverse magnetization in the recording medium.",
  "note": "The mechanism assists media switching rather than only strengthening the head's write field [toshiba-mg09-2021]. Toshiba reported a head-and-media demonstration on 27 December 2021 [toshiba-mas-demo-2021] and still described MAS-MAMR development on 22 January 2026 [toshiba-mas-research-2026]. The research status reflects those dated sources, not a complete October 2026 market audit; neither source establishes universal commercial availability. The associated paper distinguishes coupled and uncoupled oscillator modes using a resistance response to external microwave excitation, with simulations supporting the interpretation [nakagawa-injection-locking-2026]. An absent response is not a universal coupling test.",
  "status": "research",
  "advantages": [],
  "limitations": [
    "Results from a specific head-and-media demonstration do not establish performance for every HDD."
  ],
  "related": [
    "mamr",
    "fc-mamr",
    "epmr",
    "pmr"
  ],
  "supersedes": [],
  "supersededBy": [],
  "firstSeen": null,
  "lastSeen": null,
  "citations": [
    {
      "id": "toshiba-mg09-2021",
      "title": "Toshiba: High-Reliability FC-MAMR Nearline HDD with a Capacity of 18 TB (2021), p. 2",
      "url": "https://toshiba.semicon-storage.com/content/dam/toshiba-ss-v3/master/en/storage/product/data-center-enterprise/202102025_nearlineHDD_18TB_e.pdf#page=2",
      "accessed": "2026-10-16"
    },
    {
      "id": "toshiba-mas-demo-2021",
      "title": "Toshiba: Demonstration of improved HDD recording performance with MAS-MAMR (27 December 2021)",
      "url": "https://www.global.toshiba/ww/technology/corporate/rdc/rd/topics/21/2112-03.html",
      "accessed": "2026-10-16"
    },
    {
      "id": "toshiba-mas-research-2026",
      "title": "Toshiba: Analysis method for determining the oscillation state of STOs for MAS-MAMR (22 January 2026)",
      "url": "https://www.global.toshiba/ww/technology/corporate/rdc/rd/topics/26/2601-01.html",
      "accessed": "2026-10-16"
    },
    {
      "id": "nakagawa-injection-locking-2026",
      "title": "Nakagawa, Suto, Sakuraba and Maeda: Determination of coupling state within a spin-torque oscillator using injection locking, Communications Physics 9, 17 (2026), doi:10.1038/s42005-025-02469-4",
      "url": "https://www.nature.com/articles/s42005-025-02469-4",
      "accessed": "2026-10-16"
    }
  ],
  "updated": "2026-10-16"
}