Manipulation of Antiferromagnetic Metal Phase in Nd_1‐xCe_xNiO₃ by Epitaxial Strain

Abstract Antiferromagnetic metals (AFMs) are potential candidates for spintronics application owing to their insensitivity to external magnetic perturbations. However, the scarcity of AFM in complex oxide presents a significant challenge in tuning their critical properties, thereby impeding the exploration of emergent phenomena and the advancement of practical applications. Quite recently, an AFM ground state is discovered in Nd_1‐xCe_xNiO₃, an oxide whose undoped parent counterpart exhibits metal‐insulator transition dependent on temperature. Herein, the engineering of the AFM state by epitaxial strain in Nd_1‐xCe_xNiO₃ (0 ≤ x ≤ 0.07) films is demonstrated, where both Néel temperature and the metal–metal transition temperature exhibit significant response. Particularly in the 5% Ce‐doping counterpart (Nd_0.95Ce_0.05NiO₃), a suppression of the structural transition driven by compression strain causes a transition of the electronic/magnetic ground state from the AFM to paramagnetic metal. The O‐K edge X‐ray absorption spectra (XAS) reveal that strain plays a crucial role in modulating the magnetic ground state through modifying Ni─O hybridization. This work demonstrates the successful engineering of the electronic/magnetic states of AFM through epitaxial strain, providing a vital roadmap for the development of nickelate‐based AFM devices.