Nonlinear Strain-Mediated Magnetoelectric Coupling in Sub-Microscale Ni/BPZT Thin-Film Devices

Abstract

ABSTRACT Strain‐mediated magnetoelectric (ME) heterostructures enable electric‐field control of magnetism and are promising for ultra‐low‐power spintronic logic. Yet achieving spatially selective, low‐voltage control in thin films and quantifying ME coupling across the full ferroelectric strain hysteresis remains challenging. Here, we investigate sub‐micrometer Ni/BPZT thin‐film devices with laterally patterned gates that localize in‐plane strain beneath the Ni stripe and modulate its magnetization. We use anisotropic magnetoresistance to measure magnetization changes across the ferroelectric loop under different magnetic bias fields. Combined with multiphysics strain simulations and micromagnetic modeling, this work establishes a quantitative framework that captures the convolution of ferroelectric strain hysteresis and magnetoelastic nonlinearities, revealing how the magnetization evolves with ferroelectric strain under different bias fields and providing critical insight for future energy‐efficient device design. The extracted coupling coefficient in linear range is 1.3 mT V − 1 across a 700 nm gap, with a clear pathway to improving voltage efficiency through device scaling and establishing a scalable CMOS‐compatible platform for energy‐efficient spintronic devices.