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Ferroelectric Behavior in Barium Zirconium Metaniobate
Author(s) -
GOODMAN G.
Publication year - 1960
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1151-2916.1960.tb13648.x
Subject(s) - dielectric , ferroelectricity , orthorhombic crystal system , zirconium , materials science , dipole , condensed matter physics , relaxation (psychology) , barium , activation energy , hysteresis , crystal structure , crystallography , chemistry , physics , psychology , social psychology , optoelectronics , organic chemistry , metallurgy
An unusual type of ferroelectric behavior has been observed in barium zirconium metaniobate, BaNb 1.5 Zr 0.25 O 5.25 . The orthorhombic, pseudotetragonal single crystal displays dielectric hysteresis only in its c direction, with normal dielectric properties in the a‐b plane. No evidence of a fist‐ or second‐order ferroelectric‐paraelectric transition has been observed up to 1400°C. The crystal melts incongruently at about 1525°C. A maximum in the dielectric constant occurs at 80°C. when measured at 10 3 c.p.s. but is not accompanied by any effect in the spontaneous polarization. The temperature of this k′ maximum has the frequency dependence of a dielectric relaxation process with an average activation energy of 0.2 e.v. These properties are consistent with the idea of a higher than second‐order ferroelectric‐paraelectric transition in this material. The dielectric behavior is explicable in terms of 180°“dipole aggregates” having a wide range of activation energies of reversal. There are suggestions in the technical literature of similar behavior in other materials.