Transfer of High‐Temperature‐Sputtered BiFeO₃ Thin Films onto Flexible Substrates Using α‐MoO₃ Layers

Inducing external strains on highly oriented thin films transferred onto mechanically deformable substrates enables a drastic enhancement of their ferroelectric, magnetic, and electronic performances, which cannot be achieved in films on rigid single crystals. Herein, the growth and diffusion behaviors of BiFeO 3 thin films grown at various temperatures is reported on α‐MoO 3 layers of different thicknesses using sputtering. When the BiFeO 3 thin films are deposited at a high temperature, significant diffusion of Fe into α‐MoO 3 occurs, producing the Fe 1.89 Mo 4.11 O 7 phase and suppressing the maintenance of the 2D structure of the α‐MoO 3 layers. Although lowering the deposition temperature alleviates the diffusion yielding the survival of the α‐MoO 3 layer, enabling exfoliation, the BiFeO 3 is amorphous and the formation of the Fe 1.89 Mo 4.11 O 7 phase cannot be suppressed at the crystallization temperature. High‐temperature‐grown BiFeO 3 thin films are successfully transferred onto flexible substrates via mechanical exfoliation by introducing a blocking layer of Au and measured the ferroelectric properties of the transferred films.