Abstract A physical system experiences a phase transition when it goes from an ordered configuration (low temperature) to a disordered state (higher temperature). An order parameter is related to the corresponding conjugated field, that drives the system behavior. Some properties that are temperature dependent change dramatically at a so called critical temperature, indicating the point at wich the phase transition takes place. All the entities of the system contribute to the process, that is the reason why these type of processes are named cooperative phenomena. Therefore, it seems convenient to consider a mean or effective field approach as each entity is influenced, not only by an eventual external field, but for all the others. In this work we have assumed an effective field approach in order to explain some of the well-known characteristics of the pure and mixed ferroelectic crystals.

中文翻译：

---

应用于铁电相变的有效场方法

摘要 物理系统在从有序配置（低温）到无序状态（高温）时会经历相变。阶次参数与驱动系统行为的相应共轭场相关。一些与温度相关的特性在所谓的临界温度下会发生显着变化，表明发生相变的点。系统的所有实体都对过程有贡献，这就是为什么这些类型的过程被称为合作现象的原因。因此，考虑平均或有效场方法似乎很方便，因为每个实体不仅受到最终外部场的影响，而且还受到所有其他实体的影响。