Charge order and antiferromagnetism in epitaxial ultrathin films of EuNiO 3

On a road towards applications and devices based on functional oxides with correlated electrons, the crucial element is uncovering the effects of the reduced dimensionality on the electronic phase transition into a multiordered ground state. Towards this goal, we present a study of reduced dimensionality on charge and antiferromagnetic orderings in ultrathin ${\mathrm{EuNiO}}_{3}$ films on ${\mathrm{NdGaO}}_{3}$ substrates using hard and soft resonant x-ray scattering to investigate the presence of electronic and magnetic orderings. Despite the ultrathin nature of the films, they exhibit the bulklike order parameters up to room temperature, suggesting that the spontaneously coherent Mott ground state in the highly distorted rare-earth nickelates can be successfully sustained even when constrained towards two-dimensionality. The presence of charge ordering at room temperature and below opens prospects for their use in novel electric-field-controlled devices.