Domain walls in oxide thin films for neuromorphic computing

ACEVEDO, W ROMÁN; SALVERDA, MART; D RUBI; HAZRAT, S; S. FAROKHIPOOR; B NOHEDA

Congreso; Materials Research Society Fall Meeting; 2017

Ferroelastic domain walls in thin films of some complex oxides are more conducting than the domains [1][3]. It has been proposed that this effect originates from the accumulation of oxygen vacancies at the domain walls due to the presence of strain gradients [2]. This reduces the Schottky barrier present at the interface with metallic electrodes [3]. So far, conductivity has been measured locally in the out-of-plane direction by conductive AFM[1][3] and also in-plane, by macroscopic electrical measurements for both as-grown [4] and written [1] domain walls. It has also been shown that domain walls, when probed between top and bottom electrodes (out-of-plane direction), can show memristive behaviour[5]. However, the intrinsic conduction mechanisms of domain walls are still unknown.In this work, we investigate the out of plane electrical properties of metal/TbMnO3/Nb:SrTiO3 structures with different oxide thicknesses. The TbMnO3 films present a pattern of as-grown domain walls with different chemistry and magnetic properties with respect to the bulk compound [6].. Our aim is to elucidate the nature of the electrical transport properties of these domain walls and to investigate the ?electrical plasticity? and connectivity of domain wall networks in order to explore their application in neuromorphic computing.References[1] J. Seidel et al., Nature Materials 8, 229 (2009) [2] E. Salje and H. Zhang, Phase Transitions 82, 452 (2009) [3] S. Farokhipoor and B. Noheda, Physical Review Letters 107, 127604 (2011)[4] Q. He et al., Physical Review Letters 108, 067203 (2012)[5] P. Maksymovych et al., Nano Letters 11, 1906 (2011)[6] S. Farokhipoor et al., Nature 515, 379 (2014)