Antiferromagnetic Domains in NdNiO₃-based Heterostructures

Correlated oxides often exhibit the presence of intertwined phases of long-range order. The rare-earth nickelates(RNiO₃) serve as a model transition metal oxide platform to understand and engineer the electronic structure of such phases. For bulk NdNiO₃(NNO), the material undergoes a phase transition from a paramagnetic metallic phase to a charge-ordered antiferromagnetic(AF) insulating phase. Unique electronic and magnetic phase transitions exist in atomically layered NNO–based heterostructures resulting from the influences of dimensional confinement and interfacial coupling. We focus on the AF ground state in (NNO)_m-(NdAlO₃)₄ heterostructures: enhancement of AF domain dynamics and spin fluctuations in reduced dimensions appear to hinder spin ordering. We employ x-ray photon correlation spectroscopy(XPCS) measurements via coherent x-ray scattering of the heterostructures to elucidate dimensionality-driven spin dynamics. Speckle patterns arising from AF domains are investigated for different thickness of confined nickelate layers and their dynamics are studied across the charge and spin ordering transitions. This study demonstrates an approach to characterize dimensional effects on long-range order and the ability to control the AF domain configurations in oxide heterostructures.