Landau-Devonshire free energy with double-well potential
The Landau free energy for a ferroelectric:
Below Tc, the double-well creates two stable polarization states ±Pₛ. An applied field E tilts the landscape, causing sudden switching at the coercive field.
The enclosed area of the P-E loop is the energy dissipated per cycle — the signature of switching loss in capacitors and memories.