Electrical conductivity and impedance spectroscopy studies of cerium based aeschynite type semiconducting oxides: CeTiMO6 (M=Nb or Ta)

Abstract

Complex ceramic oxides, CeTiMO6 (M=Nb or Ta) having aeschynite type mineral structure were prepared by the conventional ceramic route. Complex impedance analysis in the frequency range 10 Hz–1 MHz over a wide temperature range (30–600 °C) indicates the presence of grain boundary effect along with the bulk contribution and also confirms the presence of non-Debye type of multiple relaxations in the material. The frequency dependent conductivity plots exhibit double power law dependence suggesting three types of conduction mechanisms: low frequency (10 Hz–1 kHz) conductivity owing to long range translational motion of electrons (frequency independent), mid-frequency conductivity (1–10 kHz) due to short-range hopping, and high frequency (10 kHz–1 MHz) conduction due to localized orientation hopping mechanism. The hopping model can explain the nature of the conduction mechanism completely. The electrical conductivity measurements with temperature suggest the negative temperature coefficient of resistance behavior. The activation energy studies allow insight into the nature of the conduction mechanisms.

Synthesis and characterization of B-site doped La 0.20 Sr 0.25 Ca 0.45 TiO 3 as SOFC anode materials

“…The impedance-frequency trends merge in the high frequency region irrespective of temperature. This may be due to the release of space charges as a result of reduction in the barrier properties of the material with rise in temperature and may be the responsible factor for the enhancement of ac conductivity of the material with temperature at higher frequencies [12,13]. behavior irrespective of temperature [14,15].…”

Dielectric relaxation behavior and electrical conduction mechanism in polymer-ceramic composites based on Sr modified Barium Zirconium Titanate ceramic

“…In addition at high frequency, loss minimum peak appears and shifts to the higher frequency side with temperature increases. It indicates the presence of one more relaxation mechanism due to the hopping frequency of charge carriers coincides with that of external field [15]. By addition of BSZT in the polymer matrix, more and more free charges may accumulate on the interface resulting in a decrease of relaxation time and thus, the relaxation process shift towards the higher frequencies [16].…”

Electrical conduction in (Bi0.5Na0.5)0.94Ba0.06TiO3-PVDF 0-3 composites by impedance spectroscopy

“…For small polaron hopping conduction, the value of s increases with temperature, while for large polaron hopping conduction s decreases with temperature [32]. Here, the value of s 1 first increases because of the dominance of small polaron hopping mechanism [30]. After 135°C, the slope decreases because of large polaron hopping mechanism (because the mobility of large polarons is proportional to T −1/2 ).…”

“…After 135°C, the slope decreases because of large polaron hopping mechanism (because the mobility of large polarons is proportional to T −1/2 ). Small polaron formation takes place in those materials whose conduction band belongs to the incomplete "d" or "f" orbital [30]. In the present case, Ti 3+ may be assumed to be present in the test composite samples due to the reduction of Ti 4+ of the BNBT06 ceramic constituent into Ti 3+ , thereby creating incomplete "d" orbital which may possibly be responsible for the small polaron formation.…”