Lattice distortion and strain relaxation in epitaxial thin films of multiferroic TbMnO3 probed by X-ray diffractometry and micro-Raman spectroscopy

► Highly strained (1 1 0)-oriented TbMnO3 thin films are grown by pulsed laser deposition. ► Film lattice undergoes anisotropic compressions within the epitaxial plane due to the film-substrate lattice mismatch. ► The anisotropic compressions give rise to a monoclinic distortion of the film lattice. ► A coherently strained layer is present at the interface between the film and the substrate followed by a relaxed layer. ► Anisotropic hardening of Raman-active modes with decreasing film thickness confirms the anisotropic compressive strain.