The Study on Substances having the Ilmenite Structure I. Physical Properties of Synthesized FeTiO3 and NiTiO3 Ceramics

FeTiO 3 and NiTiO 3 ceramics were synthesized, their thermal, electrical and magnetic properties were investigated and the results obtained were discussed in connection with the crystal structure. Although NiTiO 3 is stable up to high temperatures even in air, FeTiO 3 is partially oxidized even when it is cooled, being kept in vacuum (10 -5 mmHg), to room temperature from the maturing temperature (1350°C). Electrical and magnetic properties of annealed FeTiO 3 , therefore, differ greatly from those of NiTiO 3 , but properties of quenched FeTiO 3 , tend to those of NiTiO 3 . From these facts, it is concluded that the properties of NiTiO 3 are characteristics of the ilmenite structure. In discussion attention was paid especially to the relation between the ilmenite structure and its magnetic properties and to the mechanism of electrical conduction, and it was speculated, from these considerations, what kind of roles Ti 4+ ions would play in this structure.