Abstract
In order to understand the role of central atom in the nature of phase transitions in two series of ammonium oxyfluorides, A2MeO2F4 and A2A′MeOxF6-x, the permittivity was studied in wide temperature range. In most cases structural distortions are associated with the ferroelasticity. The ferro- and antiferroelectric properties were revealed only in molybdates.
Acknowledgments
This work was supported by Russian Foundation for Basic Research (Grant N09-02-00062).