Proximity Effects in Lateral Manganite Homostructures

Magnetic proximity effect (MPE) and exchange bias (EB) are hallmark interfacial phenomena in spintronics, traditionally realized at heterostructure interfaces between chemically distinct materials. However, achieving such effects in homostructures—systems composed of a single compound—remains highly challenging. Conventional epitaxial methods such as molecular beam epitaxy (MBE), atomic layer deposition (ALD), and pulsed laser deposition (PLD) often introduce chemical diffusion and compositional discontinuities, obscuring the intrinsic nature of proximity coupling.

Here, we present a novel lateral homostructure platform based on “weave epitaxy” of the prototypical correlated manganite La₀.₇Sr₀.₃MnO₃ (LSMO)【1,2】. By integrating pulsed laser deposition with freestanding oxide thin-film technology, we engineer bicrystal-like architectures that incorporate distinct strain states within a single material, thereby stabilizing coexisting ferromagnetic (FM) and antiferromagnetic (AFM) phases of LSMO in a controllable manner. Using electron-beam lithography, we patterned periodic AFM–FM junctions (~200 nm), yielding tens of thousands of sharp interfaces within a single crystal. Magnetometry measurements (SQUID) reveal both horizontal and vertical loop shifts, signifying uncompensated spins and robust FM–AFM exchange bias coupling. Temperature- and field-cooling–dependent studies further uncover the microscopic origin of these emergent self-proximity effects.

This chemically homogeneous yet electronically and magnetically heterogeneous platform demonstrates, for the first time, intrinsic MPE and EB within a single oxide compound. Beyond uncovering fundamental interfacial physics, this approach establishes a versatile design principle for spintronic devices. The demonstrated tunability of EB in homostructures opens avenues for non-volatile memory, spin valves, and reconfigurable spin logic architectures.