Dielectric and electric studies of the [N(CH3)4][N(C2H5)4]ZnCl4 compound at low temperature

The [N(CH3)4][N(C2H5)4]ZnCl4 compound was prepared and characterized by electrical technique. The temperature dependence of the dielectric permittivity shows that this compound is ferroelectric below T = 268 K. The two semi-circles observed in the complex impedance identify the presence of the grain interior and grain boundary contributions to the electrical response in the material. The equivalent circuit is modeled by a combination series of two parallel RP–CPE circuits. The frequency dependent conductivity is interpreted in term of Jonscher's law. The modulus plots can be characterized by the empirical Kohlrausch–Williams–Watts (K.W.W.) function: ϕ(t) = exp [(−t/τ)β]. The temperature dependence of the alternative current conductivity (σp), direct current conductivity (σdc) and the relaxation frequency (fp) confirm the presence of the ferroelectric–paraelectric phase transition.

► The ferro-paraelectric phase transition. ► The circuit equivalent. ► The modulus complex, conductivity and diagramme d’impedance.