Microstructure and ferroelectric properties of high-entropy perovskite oxides with A-site disorder

High-entropy oxides with complex compositions can be designed as new ferroelectric materials with interesting physical consequences. Here, a series of high-entropy perovskite ceramics (Bi 0.2 Na 0.2 Ba 0.2 Sr 0.2 Ca 0.2 TiO 3 , Bi 0.2 Li 0.2 Ba 0.2 Sr 0.2 Pb 0.2 TiO 3 , Bi 0.2 Na 0.2 Ba 0.2 Sr 0.2 Pb 0.2 TiO 3 , Bi 0.2 K 0.2 Ba 0.2 Sr 0.2 Pb 0.2 TiO 3 , and Bi 0.2 Ag 0.2 Ba 0.2 Sr 0.2 Pb 0.2 TiO 3 ) was proposed, which selected various elements to diminish the formational enthalpy and thus to achieve a single-phase structure. Detailed crystal structure and microstructure characterizations indicated that the high-entropy perovskites exhibited a single tetragonal phase with excellent chemical homogeneity. The equiatomic ratios of the A-site cations in perovskites could be used to maximize the entropy stabilization effect and effectively disordered the symmetry of the crystal structure. A robust ferroelectric polarization reaching 20 μC/cm 2 under 50 kV/cm was achieved in Bi 0.2 Na 0.2 Ba 0.2 Sr 0.2 Pb 0.2 TiO 3 high-entropy ferroelectrics. This work provides an effortless approach to discover new high-entropy ferroelectrics in materials with unexplored compositional complexity and gives additional opportunities to design and tailor the functional properties in entropy-stabilized ferroelectrics.