We investigated the resistive switching characteristics of two types of PtNiOPt structures with epitaxial and polycrystalline NiO layers. Both of these PtNiOPt structures exhibited unipolar resistive switching. Pt/epitaxial- NiOPt showed unstable switching or no resistance state change after several repeated runs. Pt/polycrystalline- NiOPt showed very reproducible switching. The experimental data indicated that microstructural defects (e.g., grain boundaries) played crucial roles in the reliability of the unipolar resistive switching behavior. This was further supported by first-principles calculations.
Bibliographical noteFunding Information:
This work was supported by the Korea Research Foundation Grant funded by the Korean Government (MOEHRD) (KRF-2007-331-C00083). S.H. and B.H.P. were supported by the National Program for 0.1 Terabit NVM Devices. B.H.P. was also supported by the KOSEF NRL Program grant funded by the Korea government (MEST) (No. R0A-2008-000-20052-0).