Determination of order parameter of YMn0.5Fe0.5O3 epitaxial thin films by anomalous X-ray scattering technique

The crystal structure of an orthorhombic YMn0.5Fe0.5O3 (010) (YMFO) epitaxial films on YAlO3(010) substrate was studied using X-ray diffraction, X-ray absorption spectroscopy, and anomalous X-ray diffraction techniques. Due to the utmost similar scattering factors of Mn and Fe atoms, it is hard to distinguish them at specific sites of the unit cell from the variations in the diffraction peak intensity. Therefore, anomalous X-ray scattering was used to determine the order or disorder structure of YMFO films. To estimate the order parameter of the YMFO film, the incident X-ray energies have been scanned around the Mn K-edge and Fe K-edge, resulting in enhanced diffraction intensities of the forbidden YMFO (010) peak by 15-20 times, respectively. This in turn revealed that YMFO films have a partially ordered structure of about 40 +/- 10% in the epitaxially grown thin film.