MAGNETISM AND SPIN TRANSPORT AT THE INTERFACE OF FERROELECTRIC AND FERROMAGNETIC MATERIALS

Abstract

Recent advances in memory technology has been driven by emerging memory architectures, especially magnetic tunnel junctions. In this work, physical effects in fabrication and MTJ operation are explored by first principles calculations. We find that carbon dopant atoms form interstitial defects at the CoFe/MgO interface upon annealing although its impact on tunnelling magnetoresistance is lesser in comparison to boron. Using an interface model for Co_xFe_1-xMgO, we predicted that minimum magnetic damping happens at x = 35%, closer to observation than seen in earlier calculations. We determined that the strong perpendicular magnetisation of Pt/Fe₂CoSi multilayers originates from orthorhombic distortion of Fe₂CoSi and the formation of the Pt/Fe₂CoSi interface. Lastly, we find that ferroelectric polarization control of magnetocrystalline anisotropy in CoFe/BaTiO₃ is achieved through modulated orbital hybridization across the interface. Interestingly, a 5<i>d</i> metal capping layer is shown to change the magnetocrystalline anisotropy drastically and strengthen ferroelectric polarization control of magnetocrystalline anisotropy.