Abstract
Antiferroelectricity is one of the most actively developing areas in modern physics due to the exceptional parameters of materials with the property. This work aims to review both the phenomenon as a whole and specific substances and their practical utilization. Both the most commonly used materials, such as lead zirconite and their analogs were identified with literature analysis. These include more environmentally friendly elements, such as silver niobate tantalate and promising hybrid compounds. Antiferroelectrics are valuable materials used in the field of energy storage and computer technology, for example, in random access memory.
Introduction
One of the areas of modern science is the discovery and study of the properties and characteristics of various materials. These features can then be applied in a wide variety of fields to obtain better and more reliable items with unique properties. Recently, science has become aware of more particles and processes acting inversely by a well-studied phenomenon. The purpose of the paper is the study of antiferroelectricity, as well as the analysis and review of materials with that property.
Antiferroelectricity
This aspect, as it becomes clear from its name, is the exact opposite of well-studied ferromagnetism. While the latter property is widely found in everyday life, the studied phenomenon is infrequent. However, it is an object of close attention of scientists because of the unique features and capabilities that this state opens. The very essence of it is antiparallel, i.e., towards each other, the arrangement of electric dipole moments in the crystals of certain substances (Electrical4U, 2019). Because of that, instead of the high magnetization of the body, as in ferromagnetism, an extremely low magnetization appears. In an object with similar property, spontaneous polarization is equal to zero since, due to their location, the dipoles in the material cancel each other out.
The reason for the rare spread of the condition is the very unusual conditions for obtaining this phenomenon. Although the requirements vary for each particular material, the principle always remains the same. It is necessary to achieve a specific temperature called the antiferroelectric Curie point to obtain an antiferroelectric phenomenon in a substance, usually a rare-earth metal (Electrical4U, 2019). Otherwise, it is called the Néel point by the scientist who discovered this phenomenon. If the material has a temperature above this value, it loses its unique properties and turns into a paramagnet. Thus, to maintain the antiferroelectric features, it is necessary to sustain the substance’s temperature in a strictly specified range. In this case, the Néel point can be as high as that of lead zirconate PbZrO3, reaching +233 degrees Celsius, or very low, dropping to couples of Kelvin degrees (Electrical4U, 2019). However, the useful attributes of these materials and their potential field of application, which also affects high energy storage devices, make them especially attractive for study.
Lead Zirconate
This material is one of the most famous antiferroelectrics and is widely used in many different areas of human activity. It is used in combination with conventional ferroelectrics and piezoelectric elements, thus expanding the scope of development of non-volatile memory (Burkovsky et al., 2017). The substance is incompletely studied due to its transitions between the magnetic phases. Therefore, the study of lead zirconate continues to this day, even though it has been known as a material for a very long time.
The mixture is a colorless crystalline compound of lead salt and zirconic acid, insoluble in water, and has the chemical formula PbZrO3. In combination with titanium, this compound is widely utilized in piezoelectric elements. In its pure form, lead zirconite is used to create many electronic and radio components, which are crucial to producing high-quality computing and energy technology. Antiferroelectric crystals are used to create various types of actuators, converters, random access memory devices, and even electronic optics (Burkovsky et al., 2017). As mentioned above, lead zirconite is also very promising in the development of energy storage.
A feature of the examination of this material is the incompletely investigated procedure for the transition between magnetic phases. As mentioned above, when forming antiferroelectric materials, the temperature is most often taken into account. Thus, the phase diagram of the dependence of temperature pressure is overestimated, since changes can also occur under the influence of other factors (Burkovsky et al., 2017). Recent studies confirm this since experimentally, two additional phases have been identified that serve as an intermediate between the antiferroelectric and cubic. The presence of new stages that have not yet been thoroughly investigated opens up additional possibilities for experiments on this material and for obtaining properties for use in technology.
Silver Niobate Tantalate
Almost all substances that fall into the category of antiferroelectrics are applied in the energy and high-tech fields. However, there are particular concerns regarding the use of materials containing lead, as previously discussed lead zirconite. Since the utilization of this material is associated with many disputes regarding environmental pollution, alternative solutions that do not include lead are actively being developed (Zhao et al., 2017). These include silver niobite tantalate, by the addition of Ta to AgNbO3, a ferroelectric/antiferroelectric that can be used for similar purposes.
This material is not only more environmentally friendly but also a better alternative to compounds such as Pb(Zr, Ti)O3. When used in the energy storage sector, a silver-based mixture shows better results than lead analogs (Zhao et al., 2017). It is characterized by high-temperature stability since the working range is designated from 20 to 120 degrees Celsius (Zhao et al., 2017). Thus, the compound can be used in a broader range of conditions, which increases the applicability of the material.
Hybrid Ferroelectric and Antiferroelectric Materials
Familiar ferroelectric materials are often contrasted with antiferroelectric due to their nature. In a way, there is competition and disputes between scientists, what kind of condition, and what type of material is more profitable and better suited for specific tasks. However, instead of dividing the elements into two groups according to their phase state, it may be worth trying to combine both sides.
Until recently, this issue was considered exclusively theoretically, without conducting any experiments. In 2018, the first hybrid material Sr3Zr2O7 was introduced, demonstrating a change in polarization at room temperature (Yoshida et al., 2018). This compound is an example of a hybrid proprietary antiferroelectricity that has not previously been encountered in practice. Although the development of this material does not mean its immediate application in practice, the study can be used to develop other types of hybrid substances. Such compounds make it possible to combine the qualities of Ferro- and antiferroelectrics for employment in thermoelectric systems. The property of phase change and competing phases can be used to improve stability.
Conclusion
Thus, antiferroelectricity is currently a rapidly developing field of research due to the many advantages provided by these materials. They can be used both in high-precision technology, random access memory, and energy storage devices. Lead zirconite is currently the most common type of this material. However, soon it can be replaced by more environmentally friendly lead-free analogs and hybrid solutions combining the advantages of Ferro- and antiferroelectrics.
References
Burkovsky, R.G., Bronwald, I., Andronikova, D., Wehinger, B., Krisch, M., Jacobs, J., Gambetti, D., Roleder, K., Majchrowski, A., Filimonov, A.V., & Rudskoy, A.I. (2017). Critical scattering and incommensurate phase transition in antiferroelectric PbZrO 3 under pressure. Scientific Reports, 7(41512), 1-8.
Electrical4U. (2019). Antiferroelectricity.
Yoshida, S., Fujita, K., Akamatsu, H., Hernandez, O., Sen Gupta, A., Brown, F.G., Padmanabhan, H., Gibbs, A.S., Kuge, T., Tsuji, R., & Murai, S. (2018). Ferroelectric Sr3Zr2O7: Competition between hybrid improper ferroelectric and antiferroelectric mechanisms. Advanced Functional Materials, 28(30), 1801856.
Zhao, L., Liu, Q., Gao, J., Zhang, S., & Li, J. F. (2017). Lead‐free antiferroelectric silver niobate tantalate with high energy storage performance. Advanced Materials, 29(31), 1701824.