Tuning electronic and magnetic properties of ultrathin and bulk magnetic oxides by adsorption of organic molecules.

Fratesi G., Achilli S., Orlando F., Marino M., Molteni E., Onida G.
  Martedì 13/09   09:00 - 13:30   Aula D - Marianna Ciccone   II - Fisica della materia   Presentazione
The surface of a magnetic material plays an important role in defining the electronic and magnetic properties of hybrid organic-inorganic interfaces for application in spintronic devices. We present first-principles density functional theory (DFT) methods to investigate the interface formed by a $C_{60}$ molecular layer on a Fe(001) surface covered by a two-dimensional $Cr_{4}O_{5}$ layer showing that the latter enhances the induced magnetic moment on the molecules by a slower decay of the spin polarization in vacuum with respect to the pristine surface. We also show that the local hybridization between the electronic states of the $Cr_{4}O_{5}$ layer and those of the organic molecules is able to modify the magnetic coupling of the Cr atoms: molecules turn the ferromagnetic intra-layer coupling into an antiferromagnetic one; further patterning of the substrate spin polarization can be achieved by controlling the adsorption site. We then investigate by Hubbard-corrected ${DFT}+U$ calculations the surface of bulk transition metal monooxides and their electronic and magnetic properties in the near surface region, studying the interaction with adsorbed molecules with/without intrinsic magnetic character.