THE EFFECTS OF IONIZING-RADIATION, TEMPERATURE AND SUBSTITUTIONS ON THE THERMOPHYSICAL PROPERTIES OF LA-FERRITE POLYCRYSTALS

Various samples of different substituted La-ferrites La1-xSmx1 (Fe1-x2 Bx2)O-3 have been prepared by the usual ceramic procedure and firing t echnique. On these samples, numerous measurements have been performed, namely, thermogravimetric analysis (TGA), differential scanning calor imetry, the temperature dependence of electrical conductivity before a nd after gamma-absorbed dose (4.5x10(7) rad) and the temperature depen dence of dielectric constant. Results obtained were explained, interpr eted and discussed in detail on the basis of interaction of the dopant cations and ionizing radiation with La-ferrite lattice. Furthermore, the thermal stability, activation energy and energy gap for semiconduc tion of the investigated ferrites were evaluated before and after gamm a-absorbed dose (4.5x10(7) rad). Finally, the activation energy for ga mma-radiation induced carrier liberation in La-ferrites was evaluated for the first time.