Impedance and electric modulus study of amorphous TiTaO thin films: highlight of the interphase effect

Abstract

The influence of phases and phase's boundaries of TiO 2 and Ta 2 O 5 in the dielectric and electric response of TiTaO (100 nm thick) elaborated by RF magnetron sputtering was highlighted by complex impedance spectroscopy. Dielectric and electric modulus properties were studied over a wide frequency range (0.1-10 5 Hz) and at various temperatures (−160 to 120 • C). The diagram of Argand (ε ′′ versus ε ′ ) shows the contribution of phases, phases' boundaries and conductivity effect on the electric response of TiTaO thin films. Moreover, the resistance of the material decreases when the temperature increases, thus the material exhibits a negative temperature coefficient of resistance. The electric modulus plot indicates the presence of two peaks of relaxation. The first relaxation process appears at low temperature with activation energy of about 0.22 eV and it is related to the first ionization energy of oxygen vacancies. The second relaxation process appears at high temperature with activation energy of about 0.44 eV. This second peak is attributed to the Maxwell-Wagner-Sillars relaxation. The plots of the complex dielectric modulus and the impedance as a function of frequency allow concluding to a localized relaxation due to the long-range conductivity in the TiTaO film.

Metal Substitution Effects on the Charge Transport and Spin Crossover Properties of [Fe1–xZnx(Htrz)2(trz)](BF4) (trz = Triazole)

“…The dispersion behavior of the electrical conductivity in the frequency domain can also be interpreted in terms of conductivity relaxation time using the electric modulus, M* = 1/ε*, representation. , In the M* representation, a relaxation peak is observed for the conductivity process in the frequency spectra of the imaginary part M ″ of the complex electric modulus M* . The frequency spectrum of the electrical modulus can be related to the mobility of the charge carriers. − In particular, the broad relaxation peak, which is often seen in the M ″ vs ω curves, represents the separation between long-range (or nonlocalized) and short-range (localized) conduction. Figure shows the frequency response of the electric modulus at selected temperatures.…”

Structure, dielectric and electrical properties of relaxor lead-free double perovskite: Nd2NiMnO6

“…The measured complex impedance (Z * ) has both real (Z ′ ) and imaginary (Z ′′ ) components described by Eq. (6) and (7) [30][31][32]:…”

Dielectric relaxations and electrical properties of Aurivillius Bi3.5La0.5Ti2Fe0.5Nb0.5O12 ceramics

“…Therefore, it is believed that the transition at ~440 o C is the ferroelectric and the high frequency relaxation originates from grains. From the log(f r )-1/T plots, the relaxation activation energies (E r a ) is calculated by the Arrhenius relation, (f r = f 0 exp (-E r a /K B T)) [32],…”