大学物理 ›› 2015, Vol. 34 ›› Issue (2): 25-25.

• 著者文摘 • 上一篇    下一篇

铁电体的介电常数

曹万强[1,2]   

  1. [1]有机化工新材料湖北省协同创新中心 [2]湖北大学材料科学与工程学院,武汉430062
  • 出版日期:2015-02-25 发布日期:2015-02-20

Dielectric constant of ferroelectrics

  • Online:2015-02-25 Published:2015-02-20

摘要: 比较了电介质物理学和铁电物理学对介电常数定义的差异.这种差异导致了解释实验结果方面相反的结论:铁电体物理学能够很好地解释极化强度增大导致介电常数减小的实验结果和外加直流电场下铁电体的介电可调行为,而电介质物理学得到的却是相反的结论.其原因是铁电材料介电常数在顺电相仅来源于横光学模的贡献,在铁电相来源于横光学模和偶极子极化,且偶极子极化会引起损耗.数学推导证实弛豫铁电行为的成份分布不是高斯分布函数.

关键词: 介电常数, 铁电体物理学, 电介质物理学

Abstract: Discrepancy of definition of dielectric constant between dielectric physics and ferroelectric physics is compared. This discrepancy leads to opposite result in explaining dielectric behavior in ferroelectric ceramics:the ferroelectric physics can properly explain the experimental phenomena of the relationship between polarization and dielectric constant,and the dielectric tenability of ferroelectrics,while dielectric physics can not. The reason is due to the softening of one of transversal optic modes in the phase transition regime,while the dipoles decreases dielectric constant and increases loss. The composition fluctuation model of Smolensky for explaining the relaxation behavior in the paraelectric phase is denied in two aspects: symbol error is found in mathematical derivation,and numerical simulation result with different distribution widths of Gaussian function is different from the observed experimental one.

Key words: dielectric constant, ferroelectric physics, dielectric physics

中图分类号: 

  • O482.4