Investigation of novel freestanding heterostructures

Abstract

Freestanding thin films exhibit novel properties and integration flexibility beyond conventional epitaxial films, enabling next-gen devices and investigation of emergent phenomena. In this thesis, we use a water membrane based lift-off and transfer technique to fabricate several freestanding heterostructures and study their functionality. Using freestanding magnetic membranes, we demonstrate the first 3D racetrack memory device, achieving efficient domain wall motion (up to 600 m s-1) in synthetic antiferromagnetic heterostructures transferred onto ~900 nm high protrusions. We also eliminate the MgO buffer layer, allowing for direct integration with target bases. Additionally, we realize twisted La2/3Sr1/3MnO3 bilayers with tunable angles, revealing anomalous diamagnetic behavior. These results highlight the versatility of freestanding heterostructures in both advanced spintronic devices and fundamental physics.