Flexible multiferroic thin films via van der Waals epitaxy

Magnetoelectric nanocomposites have been a topic of intense research due to their profound potential in the applications of magnetic sensors. In spite of significant progress made in the growth of high-quality nanocomposites via thin film deposition, the substrate clamping effect still remains a major hurdle in the realization of ultimate magnetoelectric coupling. To overcome this obstacle, an alternative strategy of fabricating self-assembled ferroelectric-ferrimagnetic bulk heterojunction on flexible muscovite via the van der Waals epitaxy is adopted. We investigated the magnetoelectric coupling in self-assembled BiFeO3 (BFO)-CoFe2O4 (CFO) bulk heteroepitaxy on muscovite wherein BFO nanopillars embedded in CFO matrix exhibit an incoherent growth with minimal substrate clamping due to the weak interaction between the substrate and bulk heterojunction. The magnetic and electrical characterizations highlight the improvement in magnetoelectric coupling of BFO-CFO bulk heterojunction. A large magnetoelectric coupling coefficient of 74 mV/cmOe desirable for the applications of highly sensitive magnetic sensor is achieved. Moreover, the fabricated heteroepitaxy on muscovite offers the additional advantage of being flexible. Therefore, this study delivers a viable route of fabricating highly-sensitive and yet flexible magnetoelectric sensors that are robust against extreme conditions with optimized performance.