Optically Programmable Antisymmetric Longitudinal Resistance Enabled by Local Domain Asymmetry

Antisymmetric longitudinal resistance (ALR) is a striking transport anomaly in perpendicularly magnetized multilayers, but its microscopic origin remains under debate. Here, we demonstrate that ALR originates from an anomalous Hall effect-induced local potential difference created by the asymmetric distribution of magnetic domains in the current−voltage intersection region. Combining multiprobe transport measurements with in situ magneto-optical Kerr imaging, we establish a direct correlation between ALR and the domain distribution in Pt/Co multilayers. We use a femtosecond laser to precisely write magnetic domains with different area fractions, thereby demonstrating that the ALR amplitude is determined by the area fraction of reversed domains within the current−voltage intersection region. Moreover, by suppressing interlayer spin-coherent transport in a spin-valve structure, we achieve a layer-resolved ALR response. Our findings clarify the microscopic origin of ALR and reveal its potential for multilevel memory and three-dimensional spintronic architectures.