Bromocholine bromide is a molecular ferroelectric with moderate phase transition temperature

The symmetry breaking originating from the order–disorder dynamic transition of organic cations results in moderate spontaneous polarization as well as switchable SHG signal and pyroelectric property with feasible “on/off” contrasts.

Pyroelectric property of SrTiO3/Si ferroelectric-semiconductor heterojunctions near room temperature

A nonlinear thermodynamic formalism is developed to calculate the pyroelectric property of epitaxial single domain [Formula: see text] heterojunctions by taking into account the thermal expansion misfit strain at different temperatures. It has been demonstrated that the crucial role was played by the contribution associated with the structure order parameter arising from the rotations of oxygen octahedral on pyroelectricity. A dramatic decrease in the pyroelectric coefficient due to the strong coupling between the polarization and the structure order parameter is found at ferroelectric [Formula: see text]–[Formula: see text] phase transition. At the same time, the thermal expansion mismatch between film and substrate is also found to provide an additional weak decrease of pyroelectricity. The analytic relationship of the out-of-plane pyroelectric coefficient and dielectric constant of ferroelectric phases by considering the thermal expansion of thin films and substrates has been determined for the first time. Our research provides another avenue for the investigation of the pyroelectric effects of ferroic thin films, especially, such as antiferroelectric and multiferroic materials having two or more order parameters.