(BiFeO3)(1-x){\Lambda}/(LaFeO3)x{\Lambda} superlattices (SLs) with varying x
have been grown by pulsed laser deposition on (111) oriented SrTiO3 substrates.
In order to obtain good epitaxy and flat samples a conducting SrRuO3 buffer has
been deposited prior to the superlattices to screen the polar mismatch for such
(111) SrTiO3 orientation. X-ray diffraction reciprocal space mapping on
different family of planes were collected and evidenced a room temperature
structural change at x=0.5 from a rhombohedral/monoclinic structure for rich
BiFeO3 to an orthorhombic symmetry for rich LaFeO3. This symmetry change has
been confirmed by Raman spectroscopy and demonstrates the different phase
stability compared to similar SLs grown on (100) SrTiO3. The strongly
anisotropic strain and oxygen octahedral rotation/tilt system compatibility at
the interfaces probably explain the orientation dependence of the phase
stability in such superlattices.Comment: 17 pages, 3 figure