Enhanced energy storage properties at phase boundary in Fe‐doped Ba(Zr 0.04 Ti 0.96 )O 3 ceramics with a slush polar state

The relationship between phase boundary and energy storage properties in x mol% Fe-doped Ba(Zr0.04Ti0.96)O3 (BZT4-xFe) ceramics was studied. The BZT4-xFe (x = 0 ~ 2) ceramics were fabricated via a conventional solid-state reaction method. The average grain size (ξ) is reduced from ~ 1.63 to ~ 1.23 μm with increasing Fe-doping content. X-ray diffraction (XRD) reveals that orthorhombic (O) and tetragonal (T) phases coexist at x = 0 ~ 0.8 and a mixing of O and cubic (C) phases was observed at x = 1 ~ 2. A slush polar state with the coexistence of O and T phases appeared near the O-T transition temperature (TO−T) in BZT4-xFe (x = 0 ~ 0.8) ceramics. A critical behavior can be observed in the BZT4-xFe ceramics. The O-T phase boundary with the slush polar state can increase the energy storage density Wrec in BZT4-xFe ceramics. The energy storage properties of BZT4-0.4Fe ceramics exhibit a good temperature, frequency, and fatigue stability.