1202.4919 (Nuala Mai Caffrey et al.)

Coexistance of giant tunneling electroresistance and magnetoresistance
in an all-oxide magnetic tunnel junction    [PDF]

Nuala Mai Caffrey, Thomas Archer, Ivan Rungger, Stefano Sanvito

We demonstrate with first-principles electron transport calculations that
large tunneling magnetoresistance (TMR) and tunneling electroresistance (TER)
effects can coexist in an all-oxide device. The TMR originates from the
symmetry-driven spin filtering provided by the insulating BaTiO3 barrier to the
electrons injected from SrRuO3. In contrast the TER is possible only when a
thin SrTiO3 layer is intercalated at one of the SrRuO3/BaTiO3 interfaces. As
the complex band-structure of SrTiO3 has the same symmetry than that of BaTiO3,
the inclusion of such an intercalated layer does not negatively alter the TMR
and in fact increases it. Crucially, the magnitude of the TER also scales with
the thickness of the SrTiO3 layer. The SrTiO3 thickness becomes then a single
control parameter for both the TMR and the TER effect. This protocol offers a
practical way to the fabrication of four-state memory cells.

View original: http://arxiv.org/abs/1202.4919