  Physical nature of "giant" magnetocaloric and electrocaloric effects, MCE and
ECE, is explained in terms of the new fundamentals of phase transitions,
ferromagnetism and ferroelectricity. It is the latent heat of structural
(nucleation-and-growth) phase transitions from a normal crystal state to the
orientation-disordered crystal (ODC) state where the constituent particles are
engaged in thermal rotation. The ferromagnetism or ferroelectricity of the
material provides the capability to trigger the structural phase transition by
application, accordingly, of magnetic or electric field.
