Flexible Epsilon Iron Oxide Thin Films

Metastable ϵ-Fe2O3 is a unique phase of iron oxide, which exhibits a giant coercivity field. In this work, we grew epitaxial ϵ-Fe2O3 films on flexible two-dimensional muscovite substrates via quasi van der Waals epitaxy. It turns out that twinning and interface energies have been playing essential roles in stabilizing metastable ϵ-Fe2O3 on mica substrates. Moreover, the weak interfacial bonding between ϵ-Fe2O3 and mica is expected to relieve the substrate clamping effect ubiquitously encountered in films epitaxially grown on rigid substrates, such as SrTiO3. It is anticipated that these flexible ϵ-Fe2O3 thin films can serve as a platform for exploring possible interesting emergent physical properties and eventually be integrated as flexible functional devices.