Epitaxial α-Mn(001) films on MgO(001)

20 nm manganese films were deposited on aMgO(001) substrate by the molecular beam epitaxy under ultrahigh vacuum conditions. The films were characterized in situ by low energy electron diffraction (LEED), electron spectroscopies and scanning tunneling microscopy (STM) and ex situ by X-ray diffraction (XRD). During the deposition the substrate was kept at room temperature. The as-deposited films did not show any distinct LEED pattern, which emerged only upon in situ annealing at 423 K, and further improved upon subsequent annealing steps at temperatures up to 623 K. The LEED pattern indicated a square surface unit cell that is commensurate with the MgO(001) substrate. STM images showed island growth of the films. The islands exposed atomically flat terraces extending approximately over 500 angstrom. The XRD analysis confirmed a single phase alpha-Mn film structure with the (001) orientation, rotated in plane by 45 degrees relative to the MgO(001) lattice. (C) 2014 Elsevier B. V. All rights reserved.