Room‐Temperature Antiferroelectricity in Titanite (CaTiSiO 5 ) Thin Films

ABSTRACT Titanite (CaTiSiO 5 ) has long been considered a promising lead–free antiferroelectric material characterized by the antiparallel displacement of Ti atoms within adjacent 1D oxygen octahedral chains. However, this antiferroelectricity has not been experimentally confirmed in recent decades. In this study, titanite thin films were fabricated on (111)Pt/(100)Si substrates using pulsed laser deposition, achieving applied electric fields up to ∼1200 kV/cm. The antiferroelectric response of the deposited titanite was confirmed through the observation of a double hysteresis loop during polarization–electric field measurements performed at room temperature. Notably, increasing the electric field induced the formation of a ferroelectric phase with a low coercive field (∼20 kV/cm), which was not observed in the bulk titanite. Measurement of the dielectric properties between room temperature and 600 K revealed a Curie temperature of ∼470 K, as indicated by a permittivity anomaly. However, the antiferroelectric response disappeared at ∼440 K, which is below the phase transition temperature. In addition, the titanite thin films demonstrated a modest recoverable energy density (0.3 J/cm 3 at ∼200 kV/cm) high energy storage efficiency (∼89% at ∼200 kV/cm).