Ferroelectric tunnel junctions

Abstract

My research is dedicated to the electronic properties of functional oxides. My activity specifically focuses on ferroelectric tunnel junctions in which an ultrathin layer of ferroelectric material is intercalated between two metallic electrodes. In these devices, polarization reversal induces large modifications of the tunnel resistance, leading to a non-destructive readout of the information. After a demonstration of the concept with scanning probe microscopy techniques, I have been exploring the properties of ferroelectric tunnel junctions with various ferroelectric materials (BaTiO3, BiFeO3, and PVDF). I showed that these devices possess attractive properties for applications as non-volatile binary memories. In addition, exploring the fact that polarization usually reverses by the nucleation and propagation of domains, I demonstrated a memristive behavior in the junctions associated to non-uniform configurations of ferroelectric domains. Such ferroelectric memristors can be used as artificial synapses in neuromorphic architectures. Coupled to magnetic electrodes, the resulting multiferroic tunnel junctions enable a non-volatile control of magnetism at the ferroelectric/electrode interface and of the spin-polarized current associated. Besides this main activity on tunnel devices, I explored the influence of ferroelectricity on magnetic orders and on the properties of functional oxides.

This is my Habilitation Thesis (HDR), defended July 13th 2017, in front of the jury composed of: Philippe Lecoeur (C2N, Paris-Saclay), Agnes Barthelemy (CNRS-Thales, Paris-Saclay), Brahim Dkhil (CentraleSupelec), Josep Fontcuberta (ICMAB), Alexei Gruverman (Univ. Nebraska), Jacobo Santamaria (Univ. Complutense Madrid)

References in corpus (19)

• Training and Operation of an Integrated Neuromorphic Network Based on Metal-Oxide Memristors
• Weak ferromagnetism and magnetoelectric coupling in bismuth ferrite
• Room temperature coexistence of large electric polarization and magnetic order in BiFeO3 single crystals
• Electric-field-induced spin-flop in BiFeO3 single crystals at room-temperature
• Theoretical current-voltage characteristics of ferroelectric tunnel junctions
• Origin of the magnetoelectric coupling effect in Pb(Zr0.2Ti0.8)O3/La0.8Sr0.2MnO3 multiferroic heterostructures
• Domain Switching Kinetics in Disordered Ferroelectric Thin Films
• Fractal dimension and size scaling of domains in thin films of multiferroic BiFeO3
• Combinatorial discovery of a lead-free morphotropic phase boundary in a thin-film piezoelectric perovskite
• The nature of domain walls in ultrathin ferromagnets revealed by scanning nanomagnetometry
• Electroresistance effects in ferroelectric tunnel barriers
• Engineering multiferroism in CaMnO${}_3$
• Real-Space and Reciprocal-Space Berry Phases in the Hall Effect of Mn${}_{1-\mathrm{x}}$Fe${}_{\mathrm{x}}$Si
• Large elasto-optic effect and reversible electrochromism in multiferroic BiFeO3
• Overcoming the Fundamental Barrier Thickness Limits of Ferroelectric Tunnel Junctions through BaTiO3/SrTiO3 Composite Barriers
• Interface effects at a half-metal/ferroelectric junction
• Monodomain to polydomain transition in ferroelectric PbTiO3 thin films with La0.67Sr0.3MnO3 electrodes
• Depth profiling charge accumulation from a ferroelectric into a doped Mott insulator
• Interfacial dead layer effects on current-voltage characteristics in asymmetric ferroelectric tunnel junctions