Structural behaviour of BiFeO3/SrRuO3 superlattices: an X-ray diffraction and Raman spectroscopy investigation

TL;DR

This study investigates the structural evolution of BiFeO3/SrRuO3 superlattices grown on LaAlO3 substrates, revealing a transition from rhombohedral to tetragonal phases as interlayer strain varies, using X-ray diffraction and Raman spectroscopy.

Contribution

It provides new insights into strain-induced structural phase transitions in BiFeO3/SrRuO3 superlattices through combined X-ray and Raman analysis.

Findings

Transition from rhombohedral to tetragonal structure with increased interlayer strain

Strain effects can be tuned by varying bilayer thickness

Structural competition influenced by epitaxial strain

Abstract

Epitaxial BiFeO3/SrRuO3 superlattices have been grown by pulsed laser deposition on a (001) oriented LaAlO3 substrate and probed by X-ray diffraction and Raman spectroscopy. To investigate the structural competition between rhombohedral BiFeO3 and orthorhombic SrRuO3 the total thickness of all SLs was kept constant and the bilayer thickness (period) {\Lambda} was varied. The interlayer strain effects are therefore tuned from large strain effects (short {\Lambda} period) to quasi-relaxed structure (large {\Lambda}). A complementary investigation using X-ray diffraction and phonon dynamics hints to change from a rhombohedral to a tetragonal structure in the superlattices with the increase of the interlayer strain effect.