Three-Dimensional Magnetic Architectures: Geometry-Driven Magnetic Properties

Abstract: Moving from planar thin-film geometries into three-dimensional (3D) architectures opens new possibilities for controlling magnetic properties through 3D geometry and curvature, enabling energy-efficient, high-density and multifunctional spintronic devices. However, fabricating high-quality 3D thin films and multilayers using different approaches introduces additional factors such as strain, thickness gradients and microstructural variations that strongly influence magnetic behavior. Disentangling these fabrication-induced contributions from intrinsic geometry- and curvature-driven magnetic behavior is a central focus of my work.

My work addresses this through two complementary platforms.

In the first, planar soft ferromagnetic microstructures are transformed into tubular architectures via polymer-based self-assembly, introducing controlled curvature and strain. By systematically varying geometric and material parameters, I isolate competing magnetoelastic and magnetostatic contributions to rolling-induced anisotropy using magnetoresistance measurements.

Building on this understanding, I demonstrate the fabrication and integration of anisotropic magnetoresistance sensors into 3D microcatheter platforms, highlighting their potential for future biomedical applications. To probe domain-wall (DW) dynamics, I developed a time-averaged magnetic force microscopy technique capable of imaging sub-100 nm DW oscillations under alternating current excitation, demonstrating that the motion follows a driven damped harmonic oscillator model, supported by micromagnetic simulations.

In the second platform, exchange-bias bilayer stacks are directly deposited onto 3D scaffolds fabricated by two-photon lithography. This enables investigation of how 3D geometries influence layer thickness, interfacial quality and magnetic properties.

Together, these platforms provide a framework for understanding how geometry and interfaces govern magnetic behavior in 3D systems, laying the groundwork for future 3D magnetoelectronic and spintronic architectures.