Density Functional Theory Investigation of Ferrimagnetic Mn<sub>4</sub>N as a Skyrmion Host
ORAL
Abstract
Skyrmion devices have potential to cause significant disruption inthe high-density storage industry. To maximize performance, nucleated skyrmions should be small and stable around room temperature. Thinfilms of ferrimagnetic Mn4N show promise with improved stability be-cause of the high N ́eel temperature, low saturation magnetization, and presence of perpendicular magnetic anisotropy in the thin film geometry. However, conditions that govern the skyrmion size in ultra-thin Mn4N films are not known. Here, density functional theory calculations are used to investigate the salient magnetic properties that govern theskyrmion size in Mn4N thin films. We calculate the impact of changing both the interfacial composition as well as orientation on the interfacial Dzyaloshinskii-Moriya interaction (iDMI). We predict that Cu substitution in the Pt capping layer reduces the iDMI, which reveals the promise of capping layer composition engineering for tuning the skyrmion size. Results from DFT are validated by growth of a < 20 nm Mn4N thin film on MgO (001) substrate with CuxPt1−xcapping layer. Imaging using magnetic force microscopy showed that in CuxPt1−x can serve as a knob to tune the skyrmion size (50–300 nm) at room temperature.
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Publication: 1) Zhou, W., et al. "Rare-earth-free ferrimagnetic Mn4N sub-20 nm thin films as potential high-temperature spintronic material." AIP Advances 11.1 (2021): 015334.<br>2) Chung T. Ma., et al. Zhou, W., et al. "Tunable Magnetic Skyrmions in Ferrimagnetic Mn4N", in review for publication in Applied Physics Letters.
Presenters
Timothy Q Hartnett
University of Virginia, Material science and engineering, University of Virginia
Authors
Timothy Q Hartnett
University of Virginia, Material science and engineering, University of Virginia
Prasanna V Balachandran
University of Virginia, Material science and engineering, University of Virginia
Chung T Ma
Department of Physics, University of Virginia, University of Virginia, Physics department, University of Virginia
Wei Zhou
Physics department , University of Virginia
Joseph Poon
Department of Physics, University of Virginia, Univ of Virginia, Physics department , University of Virginia
