Ba_0.85Ca_0.15Zr_0.10Ti_0.90O₃ (BCZT) relaxor ferroelectric ceramics exhibit enhanced energy storage and electrocaloric performances due to their excellent dielectric and ferroelectric properties. In this study, the temperature-dependence of the structural and dielectric properties, as well as the field and temperature-dependence of the energy storage and the electrocaloric properties in BCZT ceramics elaborated at low-temperature hydrothermal processing are investigated. X-ray diffraction and Raman spectroscopy results confirmed the ferroelectric–paraelectric phase transition in the BCZT ceramic. At room temperature and 1 kHz, the dielectric constant and dielectric loss reached 5000 and 0.029, respectively. The BCZT ceramic showed a large recovered energy density (W_rec) of 414.1 mJ cm⁻³ at 380 K, with an energy efficiency of 78.6%, and high thermal-stability of W_rec of 3.9% in the temperature range of 340–400 K. The electrocaloric effect in BCZT was explored via an indirect approach following the Maxwell relation at 60 kV cm⁻¹. The significant electrocaloric temperature change of 1.479 K at 367 K, a broad temperature span of 87 K, an enhanced refrigerant capacity of 140.33 J kg⁻¹, and a high coefficient of performance of 6.12 obtained at 60 kV cm⁻¹ make BCZT ceramics potentially useful coolant materials in the development of future eco-friendly solid-state refrigeration technology.

The lead-free Ba_0.85Ca_0.15Zr_0.10Ti_0.90O₃ (BCZT) relaxor ferroelectric ceramic has aroused much attention due to its enhanced piezoelectric, energy storage and electrocaloric properties. In this study, the BCZT ceramic was elaborated by the solid-state reaction route, and the temperature-dependence of the structural, electrical, piezoelectric, energy storage and electrocaloric properties was investigated. X-ray diffraction analysis revealed a pure perovskite phase, and the temperature-dependence of Raman spectroscopy, dielectric and ferroelectric measurements revealed the phase transitions in the BCZT ceramic. At room temperature, the strain and the large-signal piezoelectric coefficient reached a maximum of 0.062% and 234 pm V⁻¹, respectively. Furthermore, enhanced recovered energy density (W_rec = 62 mJ cm⁻³) and high-energy storage efficiency (η) of 72.9% at 130 °C were found. The BCZT ceramic demonstrated excellent thermal stability of the energy storage variation (ESV), less than ±5.5% in the temperature range of 30–100 °C compared to other lead-free ceramics. The electrocaloric response in the BCZT ceramic was explored via the indirect approach by using the Maxwell relation. Significant electrocaloric temperature change (ΔT) of 0.57 K over a broad temperature span (T_span = 70 °C) and enhanced coefficient of performance (COP = 11) were obtained under 25 kV cm⁻¹. The obtained results make the BCZT ceramic a suitable eco-friendly material for energy storage and solid-state electrocaloric cooling devices.

The phase transition behaviour of the chiral liquid crystal CE6 doped with spherical surface-functionalised CdSe nanoparticles has been examined by means of high-resolution adiabatic scanning calorimetry and polarising microscopy. The addition of nanoparticles results in an essentially stabilised blue phase III. The phase diagram is displayed upon heating and cooling and the enthalpy changes involved in the conversion between the blue phases are determined. The dispersion of functionalised nanoparticles is prominent for the stabilisation of blue phase III, which is potentially useful for applications, especially if applied on liquid crystals that exhibit blue phases close to room temperature.

The electrocaloric effect (ECE), i.e., the change of the temperature of the electrocaloric material due to the applied electrical field under adiabatic conditions, is a very attractive phenomenon used in a broad range of applications, for example in an electrical refrigerator. The first observations of a giant ECE were made by indirect measurements of the electrical polarization and not by direct measurements of the ECE itself. In our case, this effect was measured directly. Here a method and analysis of these direct measurements are presented and the obtained results are shown for P(VDF–TrFE–CFE) relaxor terpolymers blend with 10% composition of P(VDF–CTFE) copolymers.

Different connectivities in composite multiferroic materials.