Journal of Physical Studies 7(4), 431–448 (2003)
DOI: https://doi.org/10.30970/jps.07.431

A THEORY OF PIEZOELECTRIC, ELASTIC, AND DIELECTRIC PROPERTIES OF THE KH₂PO₄ FAMILY CRYSTALS UNDER THE STRAIN u₆. PHASE TRANSITION AND THE PIEZOELECTRIC EFFECT IN THE KH₂PO₄ CRYSTAL

R. R. Levitskii, B. M. Lisnii
Institute for Condensed Matter Physics of the Ukrainian Natl. Acad. Sci.
1 Svientsitskii Str., Lviv, UA-79011, Ukraine

In order to study the dielectric, piezoelectric and elastic properties of ferroelectrics and antiferroelectrics of the KH$_2$PO$_4$ family, we consider an extended proton tunneling model that takes into account the shear strain $u_6$. In the four-particle cluster approximation for the short-range interactions and the mean field approximation for the long-range interaction we calculate the transverse components of the dielectric susceptibility tensor of the KH$_2$PO$_4$ family ferroelectrics. We explore the phase transition and piezoelectric effect in the KH$_2$PO$_4$ crystal. In the paraelectric phase the dielectric, piezoelectric, and elastic characteristics of the NH$_4$H$_2$PO$_4$ antiferroelectrics are calculated. A good agreement between theoretical and experimental results for these crystals is obtained.

PACS number(s): 77.84.Fa, 77.65.Bn, 77.80.Bh, 77.22.Ch

A THEORY OF PIEZOELECTRIC, ELASTIC, AND DIELECTRIC PROPERTIES OF THE KH2PO4 FAMILY CRYSTALS UNDER THE STRAIN u6. PHASE TRANSITION AND THE PIEZOELECTRIC EFFECT IN THE KH2PO4 CRYSTAL

A THEORY OF PIEZOELECTRIC, ELASTIC, AND DIELECTRIC PROPERTIES OF THE KH₂PO₄ FAMILY CRYSTALS UNDER THE STRAIN u₆. PHASE TRANSITION AND THE PIEZOELECTRIC EFFECT IN THE KH₂PO₄ CRYSTAL