High-quality epitaxial growth of nanocomposite thin-films typically requires a high-temperature process on single-crystal oxide substrates
which limits their potential for flexible device integration. Here
we adopted a water-soluble Sr
3
Al
2
O
6
(SAO) sacrificial buffer layer to achieve a La
0.7
Sr
0.3
MnO
3
(LSMO):NiO freestanding nanocomposite thin film. Freestanding LSMO:NiO film has been transferred onto a flexible polymer substrate
and exhibits an exchange bias effect
and no film quality degradation has been observed after an extensive bending process. This study opens a route to fabricate high-quality freestanding nanocomposite thin films and lays a foundation towards the applications of these multifunctional nanocomposite thin films in flexible spintronic and electronic devices.