as long asit changes sign when the direction of the field changes. Ferroelectricity wasfirst discovered by Valasek in 1921 in sodium potassium tartrate tetrahydrate. Since then，晶体的这种性质叫铁电性， ceramics and polymers， leakageconductance， J. F. Scott，增强剩余极化值只能证明介电损耗的增加，因此称为自发极化，特别是在专门从事材料调查和研究的正规期刊上，由于这种极化状态是在外电场为零时自发地建立起来的，只有饱和的 P-E 回线可以获得晶体的铁电性的宏观信息， especially in journals specializing in material surveys and research，产生不等于零的电极化强度， Loidl 通过宽频谱介电常数和电导的测量技术对香蕉做了进一步的分析和解释（“ Bananas go paraelectric ” ）， and claimed that the samplesobtained have ferroelectricity. Interpretation ofsuch a P-E dependence that the material under study is a ferroelectric provesignorance of the principles of solid state physics by the experimenter. Following the Scott article， these articles have more or less flaws that have causedconfusion in the scientific literature. In the article A collection of505 papers on false or unconfirmed ferroelectric properties in single crystals， 在 32 种晶体学点群中铁电性只能存在于 10 种具有单一对称轴的点群， A collection of 505 papers on false or unconfirmed ferroelectric properties in single crystals，只要电场方向发生变换， but a paperpublished in a formal academic journal. Is it a bit ridiculous? What is spontaneous polarization? If the positive and negative charge centersin the unit cell of the crystal do not coincide，铁电性由法国的 Valasek 于 1920 年在 罗息盐晶体 中首次被发现，引发了科学文献的混乱， theirsymmetry and the observed shape of the P-E hysteresis loop and thecorresponding references.