Engineering antiphase domain boundaries boosted tunable ferromagnetic insulation

Interface-engineered superlattices composed of perovskite PrCoO3 and brownmillerite CaCoO2.5 ([(PCO)n/(CCO)n]m) were designed and fabricated on (001) SrTiO3 substrates with integrated antiphase domain boundaries (APBs) for investigating ferromagnetic insulating phenomenon. The APBs were formed at the surface-step-terrace edges, and the densities of APBs can be regulated by the periods of the superlattices. In these superlattices, ferromagnetic insulating properties were found to be significantly modulated by the APBs. The room-temperature resistivity of the n = 1 superlattice increases by more than three orders of magnitude than that of the n = 5 superlattice and more than five orders of magnitude than that of the Pr0.5Ca0.5CoO3-δ alloy films. The insulation behavior is primarily derived from the charge carriers scattering at the APBs, which block the charge carriers transferring along the in-plane direction. These results could propel the advancement of multifunctional material genetics and provide a strategic approach for the development of artificial materials with tunable properties.