Nonlinear dielectric response and positive dielectric tunability in antipolar CaTiSiO5. Issue 11 (7th July 2021)

• Record Type: Journal Article
• Authors: Murata, Tomoki; Asaka, Toru; Hirose, Sakyo
• Is Part Of: Journal of the American Ceramic Society. Volume 104:Issue 11(2021)
• Page Start: 5794
• Page End: 5802
• Publication Date: 2021-07-07
• Subjects: dielectric constant -- dielectric loss -- dielectric materials/properties -- ferroelectricity/ferroelectric materials -- silicates; Ceramics -- Periodicals; 620.1405
• DOI: 10.1111/jace.17968
• Languages: English
• ISSNs: 0002-7820

Abstract

Abstract: Dielectric tunability has been extensively investigated in ferroelectric materials, which exhibit a negative tunability of dielectric permittivity in an external electric field. In contrast, positive tunability is rare and has been reported only in a few antiferroelectric materials. We present positive (and negative) tunability in the titanite, CaTiSiO5 . The dielectric property of CaTiSiO5 was measured up to an extraordinarily high electric field of 40 MV/m. A nonlinear polarization field loop with no hysteresis was obtained. The dielectric permittivity of ε r ~ 25 increases up to ε r ~ 40 at 20 MV/m and room temperature. Although titanite has an antipolar structure and is expected to be "antiferroelectric, " its dielectric response in high electric fields up to ~40 MV/m differs from that of conventional antiferroelectrics. We demonstrate that the phase‐transition temperature and dielectric tunability could be modulated through the chemical substitution of Ca1− x La x TiSi1− x Al x O5, in which the destabilization of the long‐range antipolar order is revealed by transmission electron microscopy analysis. These results indicate that the observed dielectric response to an electric field may originate from the unique features of the antipolar and domain structures in CaTiSiO5 .