A crystal optical study of short range polar order in the ferroelectric phase: doped incipient ferroelectrics

Abstract

The temperature dependence of the principal values of the refraction of light (specific optical retardation) in Sr_1-xCa_xTiO₃ with x = 0.014, SrTi(¹⁶O_0.03¹⁸O_0.97)₃ and KTa_1–xNb_xO₃ with x = 0.018 single crystals have been measured and the magnitudes and temperature variations of polar contributions to the refraction were derived. From polar contributions to the refraction on the basis of the method developed by the authors the magnitude of the root mean square polarization fluctuations characterizing the short-range polar order in the low temperature ferroelectric phase were determined in the crystals under study.

Keywords:

• Incipient ferroelectrics
• impurities
• ferroelectric phase
• long-range order
• short-range order

Acknowledgments

We thank W. Kleemann and J.G. Bednorz for kindly providing us with the STO and SCT-1.4 crystals.

Disclosure statement

No potential conflict of interest was reported by the authors.