Despite having a very similar electrocaloric (EC) coefficient, i.e., the EC temperature change
divided by the applied electric field, the 0.9Pb(Mg1/3Nb2/3)O3–0.1PbTiO3
(PMN-10PT) ceramic
prepared by mechanochemical synthesis exhibits a much higher EC temperature change than the
columbite-derived version, i.e., 2.37 °C at 107 °C and 115 kV/cm. The difference is due to the almost
two-times-higher breakdown field of the former material, 115 kV/cm, as opposed to 57 kV/cm in
the latter. While both ceramic materials have similarly high relative densities and grain sizes (>96%,
≈5 µm) and an almost correct perovskite stoichiometry, the mechanochemical synthesis contributes
to a lower level of compositional deviation. The peak permittivity and saturated polarization are
slightly higher and the domain structure is finer in the mechanochemically derived ceramic. The
secondary phases that result from each synthesis are identified and related to different interactions
of the individual materials with the electric field: an intergranular lead-silicate-based phase in the
columbite-derived PMN-10PT and MgO inclusions in the mechanochemically derived cerami
