Lattice-strain effects on the electronic structure and magnetism of epitaxial SmCrO3 thin films

Abstract

Rare-earth orthochromites (RCrO₃) are multifunctional perovskites exhibiting coupled electronic and magnetic properties of significant interest. Spin reorientation is one such intriguing phenomenon arising from R–Cr (4f–3d) exchange interactions in these systems, mostly observed in bulk forms. In this work, we report the growth of epitaxial SmCrO₃ (SCO) thin films via a pulsed laser deposition technique and confirm the presence of a spin reorientation transition using AC/DC magnetometry. Using high-resolution X-ray diffraction, we also observe the presence of a strained lattice in the epitaxial films in comparison to the bulk SCO (−0.18% in-plane and +0.42% out of plane). Interestingly, relative to the bulk polycrystal, there is a concomitant reduction in both the Néel transition temperature (∼2%) and the optical band gap (∼3%). Our results highlight that the complex Cr–O–Cr pathways in these systems are susceptible to modest values of lattice strain, where distortions/tilts of the octahedra lead to variations in their electronic and magnetic properties. This work will thus encourage future investigations on the effects of lattice strain on strongly correlated electron phenomena in orthochromites.