Synthesis, characterization, and electrical properties of Nd3+-doped (Bi0.4Na0.2K0.2Ba0.2)TiO3 high-entropy ceramics

Abstract

Recently, high-entropy perovskites have attracted considerable attention due to their diverse chemical composition and multifunctionality. In this study, the high-entropy approach was employed in a (Bi_0.4Na_0.2K_0.2Ba_0.2)TiO₃ matrix, and Nd³⁺ was introduced to enhance the configurational entropy and modify its dielectric and ferroelectric properties. Notably, despite Nd³⁺ doping, all samples maintained a tetragonal perovskite structure at room temperature. The configurational entropy increased with the Nd³⁺ concentration, consequently leading to a gradual decline in the ferroelectric properties along with the associated temperature (T_m) and maximum dielectric constant (ε_m). The P–E loops of the ceramics also became thinner as P_m and P_r decreased, resulting in a slow decrease in the recoverable energy density (W_rec) and a simultaneous increase in the energy storage efficiency (η). Especially, the energy storage performance reached its peak at an Nd³⁺ concentration of 12 mol%, exhibiting an energy storage efficiency of 85.8% and a recoverable energy storage density of 0.74 J/cm³ at a low electric field of 100 kV/cm. These results highlight the potential of this material for dielectric applications in low electric fields and contribute to the advancement of alternative high-entropy energy storage perovskite ceramics.