Large Tunable Perpendicular Magnetic Anisotropy in Ultrathin Co -Based Ferromagnetic Films Induced by Antiferromagnetic δ−Mn

Abstract

We report on the observation of large and tunable perpendicular magnetic anisotropy (PMA) in $\mathrm{Co}$-based ferromagnetic (FM) films induced by an antiferromagnetic (AFM) $\ensuremath{\delta}\text{\ensuremath{-}}\mathrm{Mn}$ layer. The perpendicular anisotropic energy of the bilayers can be manipulated by varying the thickness of the $\ensuremath{\delta}\text{\ensuremath{-}}\mathrm{Mn}$ layer and the maximum reaches 2.41 \ifmmode\times\else\texttimes\fi{} ${10}^{7}$ erg/cm${}^{3}$. The coercivity of bilayers is also effectively regulated over a broad range from 0.02 to 7.09 T. We demonstrate that this large PMA originates from strong interfacial exchange coupling and the AFM anisotropic energy. In addition, the antisymmetric longitudinal magnetoresistance occurs in the bilayers in the absence of asymmetric geometry or magnetic field. These results enrich our understanding of AFM-induced large PMA in an AFM/FM bilayer system and provide a promising bilayer structure for exploring high-density magnetic memory devices.