The Synthesis of Perovskites Eu1-xKxTiO3 (x=0.2, 0.32) with Mixed Valence in A-Site under High Pressure and Temperature

The perovskite oxides Eu1-xKxTiO3 (x=0.2 and 0.32) were synthesized under 4.0 GPa and at 1 090 ℃ with the starting materials TiO2 and Eu2O3. XRD measurements show that the samples are cubic. 151Eu Mossbauer spectra exhibits two peaks at ca. 0 and -13 mm/s, which suggests that Eu ions are in mixed valence of +2 and +3. Only one signal with linewidth 3 140 Guss and g=2.00 is observed within the range of 480 to 6 480 G. The absence of the signals associated with Ti3+ and A-site deficiency indicates that Ti ions is Ti4+. In the process of solid state reaction, Eu3+ ions are easier reduced than Ti4+.