Ground state monoclinic (M-b) phase in (110)(c) BiFeO3 epitaxial thin films

The lattice structure of (110)-oriented BiFeO3 epitaxial thin layers has been identified by synchrotron x-ray diffraction. By using (221) and (22 (1) over bar) peaks in the (HHL) zone, a ground state monoclinic M-b phase has been observed with lattice parameters of (beta;a(m)/root 2 and c(m))=(89.35 degrees;3.985 and 3.888 angstrom). These results demonstrate a change in phase stability from rhombohedral in bulk single crystals, to monoclinic in epitaxial thin films with two domain states whose polarization is slightly tilted away from [110] towards [111]. (c) 2006 American Institute of Physics.