Giant Tunnel Electroresistance in Ferroelectric Tunnel Junctions

This chapter shows how the tunnel resistance can vary by more than two orders of magnitude upon polarization switching in highly-strained ultrathin BaTiO3 tunnel barriers. This strong electroresistance effect can be probed using a conductive AFM tip as the top electrode, or using solid-state submicron pads. Such ferroelectric tunnel junctions show large, stable, reproducible and reliable tunnel electroresistance, with resistance switching related to ferroelectric polarisation reversal. They thus emerge as an alternative to other resistive memories, with the additional advantage of not being based on voltage-induced migration of matter at the nanoscale, but on a purely electronic mechanism. Importantly, switching can be as fast as a few ns. The chapter presents data on the dynamical response of ferroelectric junctions, and their analysis with standard models of polarization reversal. Controlled Vocabulary Terms ferroelectric materials; magnetic tunnelling; optical polarization