{
  "id": "2201.03671",
  "version": "v1",
  "published": "2022-01-10T22:20:15.000Z",
  "updated": "2022-01-10T22:20:15.000Z",
  "title": "A Perspective on Electrical Generation of Spin Current for Magnetic Random Access Memories",
  "authors": [
    "Christopher Safranski",
    "Jonathan Z. Sun",
    "Andrew D. Kent"
  ],
  "comment": "12 pages, 3 figures, 1 table",
  "journal": "Applied Physics Letters 120, 160502 (2022)",
  "doi": "10.1063/5.0084551",
  "categories": [
    "cond-mat.mes-hall"
  ],
  "abstract": "Spin currents are used to write information in magnetic random access memory (MRAM) devices by switching the magnetization direction of one of the ferromagnetic electrodes of a magnetic tunnel junction (MTJ) nanopillar. Different physical mechanisms of conversion of charge current to spin current can be used in 2-terminal and 3-terminal device geometries. In 2-terminal devices, charge-to-spin conversion occurs by spin filtering in the MTJ's ferromagnetic electrodes and present day MRAM devices operate near the theoretically expected maximum charge-to-spin conversion efficiency. In 3-terminal devices, spin-orbit interactions in a channel material can also be used to generate large spin currents. In this perspective article, we discuss charge-to-spin conversion processes that can satisfy the requirements of MRAM technology. We emphasize the need to develop channel materials with larger charge-to-spin conversion efficiency -- that can equal or exceed that produced by spin filtering -- and spin currents with a spin polarization component perpendicular to the channel interface. This would enable high-performance devices based on sub-20 nm diameter perpendicularly magnetized MTJ nanopillars without need of a symmetry breaking field. We also discuss MRAM characteristics essential for CMOS integration. Finally, we identify critical research needs for charge-to-spin conversion measurements and metrics that can be used to optimize device channel materials and interface properties prior to full MTJ nanopillar device fabrication and characterization.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2022-01-10T22:20:15.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "magnetic random access memory",
      "spin current",
      "maximum charge-to-spin conversion efficiency",
      "mtj nanopillar device fabrication",
      "electrical generation"
    ],
    "tags": [
      "journal article"
    ],
    "publication": {
      "publisher": "AIP",
      "journal": "Appl. Phys. Lett."
    },
    "note": {
      "typesetting": "TeX",
      "pages": 12,
      "language": "en",
      "license": "arXiv",
      "status": "editable"
    }
  }
}