Thermomagnetic Conversion
The analog[14] of ferroelectricity is ferromagnetism. A converter employing similar principles to those in ferroelectricity can be made using an electrical inductance with a ferromagnetic core. When the temperature of the ferromagnetic material is raised above its Curie point, its magnetic permeability drops quickly, causing the magnetic field to collapse partially. Energy may be delivered to an external load during this change. Instead of energy being stored in an electrostatic field, it is stored in a magnetic field.
Ferroelectric and thermomagnetic conversion both represent a class of energy transformations which involve internal molecular or crystalline rearrangements of solids. There is no change of phase as in a steam engine, but the energy changes are there nevertheless. In thermodynamics such internal geometrical changes are called second-order transitions, as opposed to the first-order transitions observed with heat engines using two-phase working fluids like water/steam.