Ferroelectric Tunnel Junctions (FTJs)
In recent years, ferroelectric materials have attracted significant interest because of their promising potential in various technological applications. For example, due to their spontaneous dielectric polarization that can be switched by an applied electric field, ferroelectrics can be used as binary data storage media in nonvolatile random access memories. Recent experimental and theoretical findings suggest that ferroelectricity persists down to vanishingly small sizes, which opens a possibility to further miniaturize electronic devices based on ferroelectric materials. In particular, it was discovered that, in organic ferroelectrics, ferroelectricity can be sustained in thin films of a few monolayer thickness. In perovskite ferroelectric oxides, ferroelectricity was observed down to a nanometer scale. The existence of ferroelectricity at such a small film thickness makes it possible to use ferroelectrics as tunnel barriers in metal/ferroelectric/metal (M/FE/M) junctions. The electrical resistance in the ferroelectric tunnel junctions (FTJs) depends on the orientation of the dielectric polarization which can be switched by an applied electric field. In addition, by using ferroelectric as a barrier in a magnetic tunnel junctions, one can produce a multiferroic tunnel junction (MFTJ) which has new functional properties. In particular, the reversal of the electric polarization of the ferroelectric may result in a sizable change of the spin polarization of the tunneling current and tunneling magnetoresistance.
Ferroelectric Switch for Spin Injection Electron tunneling in Pt/BaTiO3/Pt FTJ |
