In physics, ferroics is the generic name given to the study of ferromagnets, ferroelectrics, and ferroelastics.
The basis of ferroics is to understand the large changes in physical characteristics that occur over a very narrow temperature range.
The changes in physical characteristics occur when phase transitions take place around some critical temperature value, normally denoted by
Above this critical temperature, the crystal is in a nonferroic state and does not exhibit the physical characteristic of interest.
Such a phase transition typically results in only a small deviation from the nonferroic crystal structure, but in altering the shape of the unit cell the point symmetry of the material is reduced.
, a spontaneous dipole moment is induced along an axis of the unit cell.
unit cells gives rise to an electric field that over the bulk substance that is not insignificant.
Here the shapes of the unit cell before and after the phase transition are different, and hence a strain is induced within the bulk.
These materials exhibit more than one ferroic property simultaneously in a single phase.