E. Haussuhl et al., ANOMALOUS DIELECTRIC, PIEZOELECTRIC AND ELASTIC PROPERTIES OF ORTHORHOMBIC NICKEL ZIRCONIUM BIS(NITRILOTRIACETATE)-CENTER-DOT-8.5-HYDRATE, NIZR[N(CH2COO)3]2-CENTER-DOT-8.5H(2)O, Zeitschrift fur Kristallographie, 213(11), 1998, pp. 559-562
Large single crystals of optical quality of nickel zirconium bis (nitr
ilotriacetate).8.5 hydrate (space group C222(1)) have been grown from
aqueous solutions. Complete elastic, thermoelastic and piezoelastic te
nsors were determined by the aid of ultrasonic methods. In addition, t
he indices of refraction, the tensor of thermal expansion, dielectric
and piezoelectric constants have been studied. Most physical propertie
s investigated show a strong anisotropy. E.g. the relative dielectric
constants epsilon(33) and epsilon(11) have values of 335 and 7, respec
tively. The static piezoelectric constant d(312) surmounts 750 pC/N (b
y more than a factor of 300 larger than d(111) Of alpha-quartz), where
as d(123) remains as low as 4 pC/N. Anomalous features are the sharp b
end of the temperature dependence of epsilon(33) at about 287 K, and,
above 280 K the increasing attenuation of transversal ultrasonic waves
propagating along [100] with displacement vector parallel to [010] an
d vice versa. These waves are related to the elastic constant c(66) Th
e anomalies and the large values of epsilon(33) and d(312) hint at a h
igher-order ferroelectric transition.