Mechanism analyses of differential and static dielectric constants in ferroelectrics. Issue 4 (26th March 2020)

• Record Type: Journal Article
• Authors: Gan, Yong C.; Cao, Wan Q.
• Is Part Of: Ferroelectrics. Volume 47:Issue 4/6(2020)
• Page Start: 96
• Page End: 104
• Publication Date: 2020-03-26
• Subjects: Ferroelectrics -- capacitivity dielectric constant; Ferroelectricity -- Periodicals; Ferroelectric crystals -- Periodicals; 537
• DOI: 10.1080/07315171.2020.1832393
• Languages: English
• ISSNs: 0731-5171

Abstract

Abstract: The dielectric constant measured by the LCR-meter is a differential-type, and is not equivalent to capacitivity. Capacitivity of ferroelectrics is the dielectric constant corresponding to electric hysteresis loop. Two kinds of dielectric constants are investigated based on the P-E loop mechanisms: turning effect of dipoles toward electric field direction, electric field-induced polarization effect, and dipole coupling effect. Numerical simulation of the theoretic equations exhibit adouble-peak of the differential dielectric constant, in which the distance between the two peaks depends on the temperature and the electric field. A much narrow static dielectric constant peak and negative peak appear corresponding to the loop. Mechanisms are analyzed schematically in detail. HIGHLIGHTS: Definitions of differential- and static-dielectric constant are introduced and compared. Theoretic equations for the two dielectric constants are derived from the three effects. Variations of the two dielectric constants with E and T are demonstrated schematically. Mechanisms of the variations are explained in detail.