Various samples of different substituted Laferrites La1–xSmx1 (Fe1–x2Bx2)O3 have been prepared by the usual ceramic procedure and firing technique. On these samples, numerous measurements have been performed, namely, thermogravimetric analysis (TGA), differential scanning calorimetry, the temperature dependence of electrical conductivity before and after -absorbed dose (4.5×107 rad) and the temperature dependence of dielectric constant. Results obtained were explained, interpreted 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 semiconduction of the investigated ferrites were evaluated before and after -absorbed dose (4.5×107 rad). Finally, the activation energy for -radiation induced carrier liberation in La-ferrites was evaluated for the first time.