Impedance spectroscopy of pellets made from yttria stabilized zirconia nanoparticles generated via CW and pulsed mode of laser vaporization method

We report impedance characteristics and ac conductivity response of ~1 mm thick pellets made from yttria-stabilized zirconia (YSZ) nanoparticles. Nanoparticles of different average sizes (10–16 nm) and of different yttria (6 mol%, 10 mol% and 16 mol%) contents were obtained via CO2 laser based laser vaporization method. We employed both the continuous and the pulsed mode of CO2 laser operation and obtained smallest size nanoparticles under pulsed mode of laser vaporization. Impedance spectroscopic measurements were carried out in frequency range of 10 Hz–1 MHz at various temperatures ranging from room temperature to 500 C. Oxygen ion conductivity response was compared with respect to laser vaporization mode and yttria content in nanoparticles of YSZ. The grain and grain boundary ionic conductivity of pellets made from large sized nanoparticles generated in continuous mode of laser vaporization was two orders of magnitude low compared to pellet made of smallest average size nanoparticles (generated with pulsed mode of laser vaporization). The activation energy of ion hopping in all the samples was estimated using Arrhenius equation and found in the range 0.95–1.34 eV. Possible origin of differences between conductivity in pellets made from nanoparticles generated via pulsed mode and CW mode of vaporization is discussed on the basis of association of oxygen vacancy and Y+3 ion.