Electrical properties of lanthanum containing vanadocalcic oxyapatite

Influence of cationic vacancies on the ionic conductivity of oxyapatites

“…The literature suggests that these two types of defects are preferentially located in 4f sites for low substitution rates. [10][11][12][13][14][16][17][18][19][20][21][22] However, it can be supposed that their repartition evolves with the extent of substitution: a certain number of these defects may come in 6h sites when the rate of substitution increases. A complete refinement of the structure of all apatites of the two series could bring further information on the evolutions of the cell parameters observed here.…”

“…15 Ionic radii are given for CN = 9: indeed, for low substitution ratios, divalent cations are supposed to be mainly located in 4f sites (CN = 9) in oxyapatites structures. 7,11,[16][17][18][19][20][21][22] All the formulations are summarized in Table 1. The aim is to observe the influence of cationic vacancies on the electrical properties of oxyapatite materials with different stoichiometries of the charge carriers.…”

Comparison of Electrical Properties between Fluoroapatite and Hydroxyapatite Materials

“…However, in lanthanum-substituted calcium vanadates Ca \V La V (VO ) O >V ) \V (04x42), the O\ ions are considered the main charge carrier (20). It was found in terms of electrical conductivity that the conduction mechanism depends on the apatite composition.…”

X-ray structure refinement, vibrational spectroscopy, and ionic conductivity of Na0.11Ca9.64Sm0.23(PO4)6F2

“…It can be elucidated through the following expression: σ=σ 0 exp(−ΔEa/kT), where σ, σ 0 , ΔEa, k, and T refer to conductivity, pre-exponential factor, activation energy, Boltzmann constant, and absolute temperature, respectively. The total activation energy was obtained as Et=0.6 eV for ionic hopping of mobile ions (Na + and F − ) along the c axis, including the bulk and grain boundary [24].…”