Ionic conductivity of LiF thin films containing Di- or trivalent metal fluorides

Evaporated LiF thin films containing MIIF2 (MII=Mg, Ca, Ni, Cu, Zn, Sr) or MIIIF3 (MIII=Al, Ti, V, Cr, Ga, Y, Ce) of less than 20 mol% are prepared and their electrical conductivity determined. It is found that fluorides of Cu, Ni, Zn, Al, Ti, V, Cr, Ga and Y increase the ionic conductivity of these thin films by up to the order of six, while those of Mg, Ca, Sr and Ce do not. These experimental results are discussed in terms of tendency to form intermediate compounds.