Hafnium oxide–based ferroelectric materials emerged as promising candidates for constructing next-generation high-density memory devices due to their silicon compatibility. However, the high coercive field (E_c, typically exceeding 1.0 MV/cm) puts forward challenges to high operating voltage and limited endurance performance. To overcome these limitations, a strategy is utilized by applying an in-situ direct current electric field during rapid thermal process (RTP). This approach enables simultaneous reduction of coercive field and enhancement of ferroelectric polarization in Hf_0.5Zr_0.5O₂ (HZO). Notably, a record-low E_c (~0.79 MV/cm) is achieved among atomic layer deposition-grown Zr-doped HfO₂ ferroelectric films, facilitating lower operation voltage, faster switching speed, and improved endurance characteristics. High-resolution transmission electron microscopy analysis reveals that the ferroelectric domains in samples through electric field assisted-RTP exhibit a relatively preferential out-of-plane orientation compared to normal RTP-treated samples, which is the underlying mechanism in reducing the coercive field and enhancing ferroelectric polarization. This study introduces a practical and effective method for optimizing the overall performance of HZO films, underscoring their potential for application in non-volatile memory technologies.

Flexible hafnia-based ferroelectric memories are arousing much interest with the ever-growing demands for nonvolatile data storage in wearable electronic devices. Here, high-quality flexible Hf_0.5Zr_0.5O₂ membranes with robust ferroelectricity were fabricated on inorganic pliable mica substrates via an atomic layer deposition technique. The flexible Hf_0.5Zr_0.5O₂ thin membranes with a thickness of -8 nm exhibit a high remanent polarization of -16 μC/cm², which possess very robust polarization switching endurance (>10¹⁰ cycles, two orders of magnitude better than reported flexible HfO₂-based films) and superior retention ability (expected >10 years). In particular, stable ferroelectric polarization as well as excellent endurance and retention performance show negligible degradations under 6 mm radius bending conditions or after 10⁴ bending cycles with a 6 mm bending radius. These results mark a crucial step in the development of flexible hafnium oxide-based ferroelectric memories for wearable electronic devices.

Room temperature electric field controlled magnetism is extremely promising for the next-generation high-performance spintronic devices. Here, based on the ferroelectric switching driven oxygen ion migration in the Ta/Co/BiFeO₃/SrRuO₃ heterostructures, the magnetic moment, magnetic coercive field, exchange bias field, and junction resistance are reversibly manipulated by tuning the ferroelectric polarization of the BiFeO₃ layer. All these phenomena are consistently explained by the oxygen ion migration induced CoO_x/Co redox effect, which is evidenced by the synchrotron X-ray absorption spectroscopy measurements. Interestingly, owing to the controllable ferroelectric switching dynamics of the BiFeO₃ thin film, the magnetic coercive field of the Co thin film can be continuously and precisely tuned by controlling the ferroelectric polarization of the BiFeO₃ thin film, and the manipulating speed of the voltage control of magnetism can be fast to 100 ns. This nonvolatile, stable, reversible, fast, and reproducible voltage control of magnetism shows great potential for designing low-power and high-speed spintronics.

Ferroelectric tunnel junctions (FTJs) as the artificial synaptic devices have been considered promising for constructing brain-inspired neuromorphic computing systems. However, the memristive synapses based on the flexible FTJs have been rarely studied. Here, we report a flexible FTJ memristor grown on a mica substrate, which consists of an ultrathin ferroelectric barrier of BiFeO₃, a semiconducting layer of ZnO, and an electrode of SrRuO₃. The obtained flexible FTJ memristor exhibits stable voltage-tuned multi-states, and the resistive switchings are robust after 10³ bending cycles. The capability of the FTJ as a flexible synaptic device is demonstrated by the functionality of the spike-timing-dependent plasticity with bending, and the accurate conductance manipulation with small nonlinearity (−0.24) and low cycle-to-cycle variation (1.77%) is also realized. Especially, artificial neural network simulations based on experimental device behaviors reveal that the high recognition accuracies up to 92.8% and 86.2% are obtained for handwritten digits and images, respectively, which are close to the performances for ideal memristors. This work highlights the potential applications of FTJ as flexible electronics for data storage and processing.