Epitaxial growth of BiFeO$_{3}$ thin films on SrTiO$_{3}$/Si substrates*

We are using molecular beam epitaxy (MBE) to grow BiFeO$_{3}$ (BFO) thin films. SrTiO$_{3 }$ (STO) on Si is used as a virtual substrate to enable the growth of BFO. Commensurate growth of STO on Si using MBE has been achieved by using co-deposition with the fluxes adjusted for stoichiometric growth and the growth rate is determined using RHEED intensity oscillations. The native oxide of the Si substrates is removed in-situ by deoxidation at around 750\r{ }C using a flux of Sr. The substrate is cooled to 500\r{ }C and additional Sr is added to form template with a (2x1) surface structure. BFO is then deposited on well-characterized STO (2-20nm thick) on Si using Fe and oxygen plasma with an overpressure of Bi flux- the growth rate being controlled by the incoming Fe flux. The RHEED pattern taken during deposition of BFO shows 2-D growth front with a 6-fold surface reconstruction. The structural and magnetic properties of the BFO samples have also been measured.