Nonlinear dielectric response and positive dielectric tunability in antipolar CaTiSiO₅

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, CaTiSiO 5 . The dielectric property of CaTiSiO 5 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 Ca 1−x La x TiSi 1−x Al x O 5 , 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 CaTiSiO 5 .

Fascinating Electrical Transport Behavior of Topological Insulator Bi2Te3 Nanorods: Toward Electrically Responsive Smart Materials

“…[23][24][25] Thus, voltage bias is believed as the most promising driving factor to change resistance or permittivity in smart microelectronic system benefiting from easy control and integration of the devices. [26][27][28][29] However, most voltage-controlled nonlinear electronic materials are limited by uncertainty about the voltage dependence of resistance or require a large bias voltage to overcome. For example, ferroelectric materials, as a kind of voltage-controlled nonlinear electronic material, [30][31][32] are difficult to achieve the same resistivity at same electric field due to hysteresis loops.…”