Synthesis and physical properties of the ferroelectric magnet SrBi3Nb2FeO12

The dielectric, elastic, and inelastic properties of a ceramic ferroelectric SrBi₃Nb₂FeO₁₂ are studied over the temperature range 300–900 K. The observed anomalies in the temperature dependences of the permitivity, dielectric loss, shear modulus, and internal friction indicate the occurrence of a structural phase transition in the compound at ～700 K. It is suggested that the transition is a proper ferroelectric and improper ferroelastic second-order phase transition.