fig1

Figure 1. Design concept and preparation of SPE film capacitor. (A-C) Micro-structure and macro-property of (A) FE, (B) RFE and (C) SPE by interface engineering and entropy optimization; (D-F) Schematic diagram of crystal structure for (D) BTO, (E) BTO/STO SLs and (F) BTO/STO-BFO SPE films. FE: Ferroelectric; RFE: relaxor ferroelectric; SPE: superparaelectric; BTO: barium titanate; STO: strontium titanate; BFO: bismuth ferrite; SLs: superlattices; P_s: saturation polarization; P_r: remanent polarization; E_b: electric breakdown strength; W_rec: recoverable energy density; W_loss: energy loss.