• • Uniaxial strain >8% and biaxial strain 5% in La0.7Ca0.3MnO3 membranes reversibly drive a metal-insulator transition by suppressing double exchange, enabling a richer strain-phase diagram.
• • The substrate clamping effect is fundamentally overcome in freestanding membranes, allowing spatially complex, reversible, and giant strain fields that are unattainable in conventional epitaxial films.
• • Mechanical manipulations such as stretching, bending, and interfacial twisting enable modulation of physical properties, including emergent polar topological structures and correlated electronic states.
• • Strain gradients frozen into the lattice via spontaneous rolling or folding generate extreme local strain gradients within minimal spatial volumes, offering new pathways for flexoelectric and twist engineering.