Ionic conduction in a ferroelectric leads to anomalous polarization switching kinetics but prevents retention failure.

To electrically control magnetic properties of material is promising toward spintronic applications, where the investigation of carrier doping effects on antiferromagnetic (AFM) materials remains challenging due to their zero net magnetization. In this work, the authors find electron doping dependent variation of magnetic orders of a 2D AFM insulator NiPS 3 , where doping concentration is tuned by intercalating various organic cations into the van der Waals gaps of NiPS 3 without introduction of defects and impurity phases. The doped NiPS 3 shows an AFM-ferrimagnetic (FIM) transition at a doping level of 0.2-0.5 electrons/cell and a FIM-AFM transition at a doping level of ≥0.6 electrons/cell. The authors propose that the found phenomenon is due to competition between Stoner exchange dominated inter-chain ferromagnetic order and super-exchange dominated AFM order at different doping level. The studies provide a viable way to exploit correlation between electronic structures and magnetic properties of 2D magnetic materials for realization of magnetoelectric effect.

How to electrically control magnetic properties of a magnetic material is promising towards spintronic applications, where the investigation of carrier doping effects on antiferromagnetic (AFM) materials remains challenging due to their zero net magnetization. In this work, we found electron doping dependent variation of magnetic orders of a two-dimensional (2D) AFM insulator NiPS3, where doping concentration is tuned by intercalating various organic cations into the van der Waals gaps of NiPS3 without introduction of defects and impurity phases. The doped NiPS3 shows an AFM-ferrimagnetic (FIM) transition at doping level of 0.2-0.5 electrons/cell and a FIM-AFM transition at doping level of ≥0.6 electrons/cell. We propose that the found phenomenon is due to competition between Stoner exchange dominated inter-chain ferromagnetic order and super-exchange dominated inter-chain AFM order at different doping level. Our studies provide a viable way to exploit correlation between electronic structures and magnetic properties of 2D magnetic materials for realization of magnetoelectric effect.

Metal-ferroelectric-insulator-silicon (MFIS) structures with SrBi2Ta2O9 as ferroelectric thin film and HfO2 as insulating buffer layer were fabricated by pulsed-laser deposition. The interfaces and memory window of the MFIS structure were investigated. Piezoresponse force microscopy was used to observe the change of domain images in order to investigate the retention characteristics, which demonstrated that the MFIS structure experiences retention loss via a random-walk-type process, identified by a stretched exponential-decay model. The corresponding mechanism was discussed based on the time-dependent depolarization field.

Ferroelectric materials have been actively incorporated into photoelectrochemical (PEC) systems in recent years. The unscreened field induced by spontaneous polarization is believed to assist the charge separation and promote the solar energy conversion. However, the robustness of ferroelectricity in nanoscale heterostructures is plagued by detrimental size effects. Here, we report the unexpected improvement of PEC water splitting in BaxSr1−xTiO3/TiO2 rod–shell nanostructures with suppressed ferroelectric polarization. We propose that the enhanced electrical susceptibility due to ferroelectric instability facilitates the formation of ferroelectric polarons that protect the photocarrier transport from adverse recombinations with charged defects and opposite carriers, thus increasing the carrier lifetime and eventually boosting the cell efficiency. The results demonstrate the influence of dynamic polar order engineering on the photocarrier transport kinetics in ferroelectric-related PEC applications.