Photostriction‐Driven, Light‐Modulated Magnetization in Fe/PMN‐PT Heterostructures

Abstract Optical control of ferroic order offers a transformative route for manipulating magnetic states in multiferroic systems, especially at ferromagnetic/ferroelectric (FM/FE) interfaces. However, achieving stable, reversible, and room‐temperature modulation of magnetism via light remains a key challenge, primarily due to limited coupling efficiency and poor structural control at the nanoscale. This limitation can be overcome by utilizing strain‐mediated coupling mechanisms that convert photostrictive responses in the FE layer into magnetic reorientation in the FM layer. Here, a reversible, light‐induced strain effect is demonstrated in PMN‐PT single crystals, where domain variants visualized via Piezoresponse Force Microscopy undergo controlled reconfiguration under visible laser illumination. X‐ray diffraction reciprocal space maps confirm lattice deformation, while Raman spectroscopy reveals local structural changes. In Fe/PMN‐PT heterostructures, this optically induced strain drives magnetic axis reorientation in the Fe layer, confirming robust magneto‐electric coupling. The discovery establishes a non‐contact, energy‐efficient approach to manipulate magnetism, advancing the field toward ultrafast, reconfigurable magneto‐optical devices.