Room-Temperature Ferroelectric Resistive Switching in Ultrathin Pb(Zr_0.2Ti_0.8)O₃ Films

Abstract

Spontaneous polarization of ferroelectric materials has been for a long time proposed as binary information support, but it suffers so far from destructive readout. A nondestructive resistive readout of the ferroelectric polarization state in a metal-ferroelectric-metal capacitor would thus be advantageous for data storage applications. Combing conducting force microscopy and piezoelectric force microscopy, we unambiguously show that ferroelectric polarization direction and resistance state are correlated for epitaxial ferroelectric Pb(Zr(0.2)Ti(0.8))O(3) nanoscale capacitors prepared by self-assembly methods. For intermediate ferroelectric layer thickness (∼9 nm) sandwiched between copper and La(0.7)Sr(0.3)MnO(3) electrodes we achieved giant electroresistance with a resistance ratio of >1500 and high switching current densities (>10 A/cm(2)) necessary for effective resistive readout. The present approach uses metal-ferroelectric-metal devices at room temperature and, therefore, significantly advances the use of ferroelectric-based resistive switching.

Tunnel electroresistance in junctions with ultrathin ferroelectric Pb(Zr0.2Ti0.8)O3 barriers

“…Details of the growth and fabrication process can be found elsewhere. 7 In particular, structural and electrical quality of the LSMO and PZT layers used in the present study are similar to those used in Ref. 7.…”

“…[3][4][5][6][7][8][9][10][11][12] However, there are mechanisms other than ferroelectric polarization switching, which might contribute to or generate a resistive switching effect, such as, for instance, surface electrochemical reactions. 4,13 Especially, experiments performed in ambient conditions by using a conductive atomic force microscope (AFM) tip in contact with a ferroelectric surface are prone to such effects.…”

“…9 nm) has already been performed. 7 In these studies, Schottky emission was suggested as the dominating transport mechanism. For smaller barrier thickness, direct tunneling should be the dominant transport mechanism, as predicted by theoretical simulations.…”

Giant electrode effect on tunnelling electroresistance in ferroelectric tunnel junctions

“…Nevertheless, high-quality epitaxial films grown on suitable substrates were found to possess necessary ferroelectric properties even at nanoscale thicknesses [14][15][16][17][18] , which may be attributed to the enhancement of the out-of-plane polarization by substrate-induced lattice strains 19 and the elastic stabilization of a single-domain state 20 . Based on these advancements, various FTJs have recently been successfully fabricated and the TER effect was revealed experimentally and confirmed theoretically [21][22][23][24][25][26][27][28][29][30][31] . Moreover, the functioning of solid-state memories based on FTJs has been demonstrated 3,32 and the memristive behaviour with resistance variations exceeding two orders of magnitude was observed for FTJs with the BaTiO 3 (BTO) barrier 32,33 .…”

“…The choice of electrode materials, due to different screening and chemical properties at the interface, seems to have pronounced influence on the TER effect [21][22][23][24][25][26][27][28][29][30][31][32][33] . Therefore, it is essential to examine the impact of different electrode materials on the TER characteristics of FTJs.…”