O 30 compound has been prepared by solid-state reaction technique. Compound is found to be single phase by XRD studies. SEM study indicates average grain size to be ∼3 µm. Dielectric studies carried out in temperature regime RT-773 K and frequency range 1 Hz-100 kHz, show ferroelectric phase transition at 550 K at 100 kHz. The impedance spectra show three distinct regions in temperature range 543-663 K corresponding to electrode polarization, grain boundary and grain interior contributions and indicate ionic behavior. The activation energy has been evaluated following Arrhenius equation to be 0.51 eV.

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Polycrystalline sample of Ba5HoTi3V7O30 was prepared using solid-state reaction technique. X-ray structural analysis indicated a single-phase formation with orthorhombic structure. Microstructural study by SEM showed non-uniform distribution of grains over the surface of the sample. Impedance and modulus spectroscopy studies were carried out, as functions of frequency (42 Hz - 5 MHz) and temperature (RT-773K). The Nyquist plots clearly showed the presence of both bulk and grain boundary effect in the compound. Electrical phenomena in the material can appropriately be modeled in terms of an equivalent circuit with R, C and CPE in parallel. The fitting procedure used here allows us to determine the value of R and C with good precision. Here R2 and R3 correspond to the resistance contributed from the grain boundary and bulk, respectively. C1 and C2 correspond to the capacitance contributed from the grain boundary and bulk, respectively. The real part of electrical modulus shows that the material is highly capacitive. The asymmetric peak of the imaginary part of electric modulus M″, predicts a non Debye type relaxation. The activation energy of the compound (calculated both from impedance and modulus spectrum) is same, and hence the relaxation process may be attributed to the same type of charge carriers

The ferroelectric ceramic Ba 5 LaTi 3 V 7 O 30 has been synthesized by solid-state reaction technique. Preliminary X-ray structural analysis confirmed a single-phase formation (orthorhombic crystal system) of the compound. Surface morphology of the compound was studied by scanning electron microscopy (SEM). Detailed studies of electrical properties (i.e., dielectric constant, loss tangent, ac and dc conductivity) as a function of temperature (RT -773 K) at four different frequencies, 1 kHz, 10 kHz, 100 kHz and 1 MHz show ferroelectric-paraelectric phase transition of the compound. The impedance spectra show two distinctly separated regions in wide temperature range corresponding to grain boundary and grain interior contributions. The activation energy has been evaluated from ac conductivity and dc conductivity following Arrhenius equation is 0.15 eV at 1 MHz and 0.28 eV, respectively. The temperature dependence of electrical conductivity shows that the conductivity increases with increase in temperature suggesting that the compounds have a negative temperature coefficient of resistance (NTCR) behaviour. The conductivity pattern shows that it is strongly frequency dependent and obeys Jonscher's power relation.