Voltage‐Driven Non‐Volatile Interconversion Between Giant Single‐Domain and Multidomain Magnetic States in a Multiferroic Heterostructure

ABSTRACT Voltage control of magnetic states in multiferroic heterostructures represents a promising route toward voltage‐programmable magnetic devices. However, it remains challenging to achieve deterministic and non‐volatile electrical control of well‐defined magnetic states without the assistance of a magnetic field. Here we demonstrate repeatable and non‐volatile voltage‐driven interconversion between giant single‐domain and multidomain magnetic states in a strain‐coupled heterostructure comprising permalloy (Py) and 0.68Pb(Mg 1/3 Nb 2/3 )O 3– 0.32PbTiO 3 (011) pc (PMN‐PT) (pc = pseudocubic). Growth‐induced in‐plane uniaxial magnetic anisotropy yields a square hysteresis loop, indicating a remanent monodomain state that is consistent with 15 µm‐diameter XMCD‐PEEM images. Low‐voltage biasing of the PMN‐PT substrate repeatably induces a ∼90° in‐plane rotation of the magnetic easy axis and the concomitant formation of a multidomain state. At higher voltages, the easy axis rotates back to its original orientation, restoring the monodomain state. Cycling the ferroelectric substrate through minor loops near the coercive field yields non‐volatile and repeatable switching between the multidomain and monodomain states. These results provide a pathway for voltage‐programmable engineering of magnetic single‐domain states in multiferroic heterostructures.