In the present investigation, we have experimentally demonstrated the coexistence of filamentary and homogeneous resistive switching mechanisms in single Al/MnO 2 /SS thin film metal-insulator-metal device. The voltage-induced resistive switching leads to clockwise and counterclockwise resistive switching effects. The present investigations confirm that the coexistence of both RS mechanisms is dependent on input voltage, charge-flux and time. Furthermore, the non-zero I-V crossing locations and crossovers hysteresis loops suggested that the developed device has memristive and meminductive properties. The memristive and meminductive memory effects are further confirmed by electrochemical impedance spectroscopy. The results suggested that the mem-device dynamics and electrochemical kinetics during different voltage sweeps and sweep rates are responsible for the coexistence of filamentary and homogeneous resistive switching mechanisms as well as memristive and meminductive memory effect in single Al/MnO 2 /SS metal-insulator-metal device. The coexistence of both RS effects is useful for the development of high-performance resistive memory and electronic synapse devices. Furthermore, the coexistence of memristive and meminductive memory effects is important for the development of adaptive and self-resonating devices and circuits.

Domain walls separating regions of ferroelectric material with polarization oriented in different directions are crucial for applications of ferroelectrics. Rational design of ferroelectric materials requires the development of a theory describing how compositional and environmental changes affect domain walls. To model domain wall systems, a discrete microscopic Landau–Ginzburg–Devonshire (dmLGD) approach with A‐ and B‐site cation displacements serving as order parameters is developed. Application of dmLGD to the classic BaTiO3, KNbO3, and PbTiO3 ferroelectrics shows that A–B cation repulsion is the key interaction that couples the polarization in neighboring unit cells of the material. dmLGD decomposition of the total energy of the system into the contributions of the individual cations and their interactions enables the prediction of different properties for a wide range of ferroelectric perovskites based on the results obtained for BaTiO3, KNbO3, and PbTiO3 only. It is found that the information necessary to estimate the structure and energy of domain‐wall “defects” can be extracted from single‐domain 5‐atom first‐principles calculations, and that “defect‐like” domain walls offer a simple model system that sheds light on the relative stabilities of the ferroelectric, antiferroelectric, and paraelectric bulk phases. The dmLGD approach provides a general theoretical framework for understanding and designing ferroelectric perovskite oxides.

Prediction of properties from composition is a fundamental goal of materials science that is particularly relevant for ferroelectric perovskite oxide solid solutions where compositional variation is a primary tool for material design. Design of ferroelectric oxide solid solutions has been guided by heuristics and first‐principles and Landau–Ginzburg–Devonshire theoretical methods that become increasingly difficult to apply in ternary, quaternary, and quintary solid solutions. To address this problem, a multilevel model is developed for the prediction of the ferroelectric‐to‐paraelectric transition temperature (Tc), coercive field (Ec), and polarization (P) of PbTiO3‐derived ferroelectric solid solutions from composition. The characteristics of the materials at different length scales, starting at the level of the electronic structure and chemical bonding of the constituent ions and ending at the level of collective behavior, are analytically related by using ferroelectric domain walls and cationic off‐center displacements as the key links between the different levels of the model. The obtained composition–structure–property relationships provide a unified quantitatively predictive theory for understanding PbTiO3‐derived solid solutions. Such a multilevel analytical modeling approach is likely to be generally applicable to different classes of ferroelectric perovskite oxides and to other functional properties, and to materials and properties beyond the field of ferroelectrics.

Ferroelectric perovskite solid solutions are of interest due to their extensive use in modern electronic devices. Cation off-centering is the dominant mechanism of ferroelectricity in perovskite oxides, and it was shown that the average off-centering of these cations can be used to predict some of the essential properties of solid solutions. In this work, we use first-principles density functional theory to investigate the dependence of the cation displacements on the ionic size, amount of substitution, O6 tilt, and locations of the Bi and Me3+ cations in xBiMe3+O3–(1 − x)PbTiO3 (Me3+ = Ga, Sc, In) solid solutions. We carry out our calculations for the x = 0.125 and x = 0.25 BiMe3+O3 substitution concentrations and the ⟨100⟩, ⟨110⟩, ⟨111⟩, ⟨011⟩, and ⟨001⟩ arrangements of the BiMe3+O3 substituent units. We demonstrate that the substitution of larger ions leads to greater variation in the energy and cation displacement magnitudes of the different cation arrangements. Our study reveals that cation displacements are governed by the interplay of the volume expansion effect that favors higher displacements and the cooperative O6 tilt effect that decreases the displacements. Both of these effects increase with greater ionic radius and their relative strengths depend on the cation arrangement. We also illustrate how negative pressure can be achieved experimentally by the doping of large In cations in these solid solutions. Understanding the dependence of the different directional arrangements, O6 tilting, and the effect of ionic size is important for precise prediction of ferroelectric materials properties and enables rational design of new piezoelectric materials.

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