摘要
Lithium titanate(Li_(2)TiO_(3))is one of the most promising candidates among the tritium breeding materials because of its good tritium release capacity.Li concentration has much significance on the diffusivity of tritium in the material.The nanocrystalline single-phase Li_(2)TiO_(3) with monoclinic structure has been prepared by high energy ball milling followed by calcination at 700℃for 2 h.The field emission scanning electron microscopy(FESEM)studies confirmed uniform distribution of nanocrystalline phase with particle size below 100 nm.The study of the Li^(+)ion diffusion on the sintered sample was investigated by means of electrical conductivity measurements.Electrical properties of the samples were studied in wide temperature(50-500℃)and frequency(100 Hz-1 MHz)ranges.The complex impedance spectroscopy(CIS)studies showed the presence of both bulk and grain boundary effects in nanocrystalline Li_(2)TiO_(3).The bulk resistance of the samples has been observed to decrease with rise in temperature showing a typical negative temperature coefficient of resistance(NTCR)behavior.The low activation energies of the samples suggested the presence of singly ionized oxygen vacancies in the conduction process.The hopping frequency shifted toward higher frequency with increase in temperature.Activation energy of 0.86 eV was calculated from AC conductivity.
基金
We thank the Board of Research in Fusion Science and Technology(BRFST),Institute for Plasma Research Gandhinagar,India for financial support of the research(Grant No.NFP/MAT/F10/01).
