Synergistically optimizing electrocaloric effects and temperature span in KNN-based ceramics utilizing a relaxor multiphase boundary

Abstract

Enhanced ΔT and widened Tspan simultaneously utilizing a relaxor multiphase boundary in KNN-based ceramics.

Enhanced electrocaloric effect in compositional driven potassium sodium niobate‐based relaxor ferroelectrics

“…Figure 5(g) displays the heat flow consequences obtained by using the modified DSC instrument to validate the fulfilling indirect ECE properties of the ceramics with x = 0.13. It is noted that the applied external electric fields could produce an uphill exothermic peak, while a decurrent endothermic peak is observed when the electric fields withdraw from the samples [14]. It can be seen that both the exothermic and endothermic peaks increase with the aggrandized applied electric fields, and presenting a reversible ECE and an increased ΔT value with the increased electric fields as well, as shown in Figs.…”

“…The ΔT value is almost doubled when the external applied electric field elevated from 40 to 65 kV/cm, proving the significant contribution of electric field to ECE performance. ceramics with FF or FP transitions [12,13,14,34,38,39,40,41]. It can be seen that the ΔT values of this work exceed most of the other KNN-based ceramics under the same or higher electric fields, illustrating that the ceramics prepared in this work are hopeful materials for practical refrigeration applications.…”

“…A higher electrocaloric response of 1.19 K could be attained at ferroelectric-paraelectric (FP) phase boundary under 35 kV/cm [13]. And a larger ΔT value of 0.63 and 1.9 K could be observed under 80 and 159 kV/cm at around FF and FP, respectively [7,14]. As a result, both the FP phase transition and the large applied electric field are beneficial for obtaining high ΔT values [6].…”

“…Figure 7: (a) Comparison of ΔT values of this work (the red star) and other KNN-based ceramics under different electric fields [12, 13, 14, 34, 38, 39, 40, 41]; (b) Distribution of temperature span of different ΔT values; (c) Comparison of the temperature span of ΔT values among this work and other KNN-based ceramics (at 40 kV/cm)[12,14,40]; Out-of-plane PFM amplitude and phase images of (d) x = 0.11, (e) x = 0.13, and (f) x = 0.15 ceramics.…”

Emergent Enhanced Electrocaloric Effect within Wide Temperature Span in Laminated Composite Ceramics

“…There has also been interest in seeking better ECE properties, [ 12 ] including by optimizing the balance between Δ T max and T span in relaxor ferroelectric in the vicinity of the morphotropic phase boundary (MPB). For example, the ceramic system (1 − x )BaZr 0.2 Ti 0.8 O 3 − x Ba 0.7 Ca 0.3 TiO 3 with x = 0.3 displays a tricritical point (TP) in its MPB and exhibits a very wide ECE peak.…”