Phase transition close to room temperature in BiFeO3 thin films
  BiFeO3 (BFO) multiferroic oxide has a complex phase diagram that can be mapped by appropriately substrate-induced strain in epitaxial films. By using Raman spectroscopy, we conclusively show that films of the so-called supertetragonal T-BFO phase, stabilized under compressive strain, displays a reversible temperature-induced phase transition at about 100\circ, thus close to room temperature. 
J. Kreisel, P. Jadhav, O. Chaix-Pluchery, M. Varela, N. Dix, F.   Sanchez and J. Fontcuberta
cond-mat.mtrl-sci