CATION DISTRIBUTION INVESTIGATION OF THE SYSTEM LI0.5FEXGA2.50-XO4 BYX-RAYS, ELECTRICAL-CONDUCTIVITY AND MOSSBAUER STUDIES

Structural, electrical and Mossbauer studies were carried out for the system Li0.5FexGa2.5-xO4. All the compounds with 0 less-than-or-equal- to x less-than-or-equal-to 2.5 crystallised with cubic spinel structur e. Lattice constant values calculated from XRD analysis were found to increase with increasing x. X-ray intensity calculations indicated tha t Li1+ occupies only the octahedral site and Ga3+ and Fe3+ ions occupy both octahedral and tetrahedral sites. Activation energy and thermoel ectric coefficient values decreased with increasing values of x. All t he compounds studied were p-type semiconductors and possess low mobili ty values of 10(-7) - 10(-9) cm2 V-1 s-1. Mossbauer data show the pres ence of iron in the Fe3+ state and the isomer shift values for all the compositions of the system are within the range of high spin ferric c ompounds. The probable ionic configuration for the system is suggested as: Fealpha3+[Li0.5(1+)Fex-alpha3+Ga2.5-x+alpha3+]O42-