Towards hexagonal C2v systems with anisotropic Dzyaloshinkii-Moriya interaction: Characterization of epitaxial Co(101¯0)/Pt(110) multilayer films

Abstract

Ferromagnet/heavy metal (FM/HM) multilayer thin films with ${C}_{2v}$ symmetry have the potential to host antiskyrmions and other chiral spin textures via an anisotropic Dzyaloshinkii-Moriya interaction (DMI). Here, we present a candidate material system that also has a strong uniaxial magnetocrystalline anisotropy aligned in the plane of the film. This system is based on a new Co/Pt epitaxial relationship, which is the central focus of this work: hexagonal closed-packed $\mathrm{Co}(1\phantom{\rule{0.16em}{0ex}}0\phantom{\rule{0.16em}{0ex}}\overline{1}\phantom{\rule{0.16em}{0ex}}0)[0\phantom{\rule{0.16em}{0ex}}0\phantom{\rule{0.16em}{0ex}}0\phantom{\rule{0.16em}{0ex}}1]$ $\ensuremath{\parallel}$ face-centered cubic $\mathrm{Pt}(1\phantom{\rule{0.16em}{0ex}}1\phantom{\rule{0.16em}{0ex}}0)[0\phantom{\rule{0.16em}{0ex}}0\phantom{\rule{0.16em}{0ex}}1]$. We characterized the crystal structure and magnetic properties of our films using x-ray diffraction techniques and magnetometry, respectively, including $q$-scans to determine stacking fault densities and their correlation with the measured magnetocrystalline anisotropy constant and thickness of Co. In future ultrathin multilayer films, we expect this epitaxial relationship to further enable an anisotropic DMI while supporting interfacial perpendicular magnetic anisotropy. The anticipated confluence of these properties, along with the tunability of multilayer films, make this material system a promising testbed for unveiling new spin configurations in FM/HM films.