Ca3Ti2O7 with a Ruddlesden–Popper structure has received great scientific attention due to its high ferroelectric polarization. However, the optimization of hybrid improper ferroelectricity is still a challenging issue. In the present work, the remarkably improved ferroelectric polarization has been achieved in B-site co-substituted Ca3Ti1.8Al0.1Nb0.1O7 ceramic. The improved ferroelectric polarization in this ceramic stems from the higher ferroelectric activity of Nb5+ cations and a larger amplitude of oxygen octahedral distortion. Moreover, the more saturated electric hysteresis loops together with the higher ferroelectric polarization can be achieved under a higher electric field and at a lower frequency. The first-order phase transition nature is proved by the thermal hysteresis, while the Curie temperature is directly proportioned to the tolerance factor. The present work provides an effective way to improve the ferroelectric properties without declining the Curie temperature in Ca3Ti2O7-based hybrid improper ferroelectricities.

中文翻译：

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具有 Ruddlesden-Popper 结构的 B 位取代 Ca3Ti2O7 陶瓷中混合不当铁电性的改进

具有 Ruddlesden-Popper 结构的 Ca3Ti2O7 由于其高铁电极化而受到了极大的科学关注。然而，混合不当铁电性的优化仍然是一个具有挑战性的问题。在目前的工作中，在 B 位共取代 Ca3Ti1.8Al0.1Nb0.1O7 陶瓷中实现了显着改善的铁电极化。这种陶瓷中铁电极化的改善源于 Nb5+ 阳离子更高的铁电活性和更大幅度的氧八面体畸变。此外，可以在更高的电场和更低的频率下实现更饱和的电滞回线以及更高的铁电极化。一阶相变性质由热滞后证明，而居里温度与容差系数成正比。目前的工作提供了一种有效的方法来提高铁电性能而不降低基于 Ca3Ti2O7 的杂化不当铁电体的居里温度。