Large Room Temperature Electrocaloric Effect in KTa_1−xNb_xO₃ Single Crystal

Component regulation has a significant influence on the ferroelectric structural phase-transition characteristics such as the temperature (T_c) and the functional properties. Here, the electrocaloric (EC) properties in potassium tantalate niobate (KTa_1−xNb_xO₃) single crystal are reported. The KTN43 (x = 0.43) single crystal exhibits an adiabatic temperature change of ΔT = 0.76 K at 15 kV cm⁻¹ with both the first-order and the diffuse phase transition performances near T_c. It represents a good solution for the two intractable contradictions for electrocaloric effect (ECE), namely that the large EC peak value prevents a low working temperature and a wide temperature span. It is shown that improving the Nb component in KTN single crystal can obviously elevate the EC properties. KTN shows good EC properties, including large adiabatic temperature change, low driving electric fields, large refrigeration capacity, working near room temperature and reversibility for all temperature range. These properties indicate that KTN is a promising EC material for practical application.