Piezocaloric effect

Figure 1.32 The well-known triangle used to describe the pathways between mechanical, electrical, and thermal energies in a class of noncentrosymmetric materials exhibiting piezoelectric effect, pyroelectric effect (converse of electrocaloric effect), piezocaloric effect (converse ofthermal expansion), and so on. For...

AS, entropy (C/T) AT, heat capacity C, divided by T Pi Et, electrocaloric effect q, Hi, magnetocaloric effect ay <3y, piezocaloric effect... 

The above scheme actually involves 9 + 3+ 1 =13 distinct equations, each containing 13 independent variables. Proceeding across the various entries we find the following (1,1) elasticity, all (Trs except u / remain fixed (1,2) converse piezoelectricity (1,3) thermal expansion (2,1) direct piezoelectricity, all ffrs except ajk remain fixed (2,2) electrical permittivity (2,3) pyro-electrity (3,1) piezocaloric effect, all Urs except [Pg.324]

These Maxwell relations show that the matrix elements in Eq. (5.11.2) are symmetric about the diagonals. Specifically, the coefficients of the direct and converse piezoelectric effects are equal—a conclusion that verifies an earlier statement in Section 5.10. Also, the coefficients for the thermal expansion and for the piezocaloric, as well as for the pyroelectric and electrocaloric effects, respectively, are identical. Again, bear in mind that Eq. (5.11.2) represents six relations for e,-, three relations for Dj, and one equation for d5, each of which contains six variables Uy, three variables ,-, and Tas the independent quantities. 

Heat evolved by applying mechanical stress (piezocaloric effect)... 

---