Antiferromagnetic Domain Dynamics in Nickelate Heteorstructures

Understanding the energetics of the antiferromagnetic (AF) domains and the timescale of their fluctuations in a magnetic material are important for its application in spin-based electronics. NdNiO₃ (NNO) undergoes an AF transition at ~150K, and thus it serves as an oxide platform to study and engineer its AF ground state. We investigate how dimensional confinement leads to phase fluctuations in atomically layered (NdNiO₃)_m/(NdAlO₃)_n heterostructures through x-ray photon correlation spectroscopy (XPCS). The speckle patterns arising from coherent x-ray scattering provide the information on long- and short- ranged correlations for different heterostructures with varying thickness of nickelate layers, m, and aluminate layers, n. We find that the dynamics of the AF domain boundaries are dramatically enhanced as the dimensionality of the NNO layers are reduced, approaching the 2D limit. The dynamics of AF domain fluctuations in the heterostructure can be further tailored by tuning the interlayer coupling of nickelate layers. Our study demonstrates a path to characterize any long-range orders in quantum materials under dimensional effect and enables us to control AF domain configurations in oxide heterostructures.