Electronic Structure and Crystal Structure of Multiferroic o-YMnO3 at High Temperature

Abstract

The dependence of the electronic structure and crystal structure of multiferroic YMnO3 in an orthorhombic phase (o-YMnO3) on temperature up to 873 K was investigated on combining the measurements of synchrotron x-ray powder diffraction (SXRD) and high-resolution x-ray absorption spectra measured in the partial fluorescence yield. Based on SXRD refinement, the small equatorial bond distance (Mn–O2)s of o-YMnO3 increases progressively, whereas the large equatorial bond distance (Mn–O2)l decreases with increasing temperature. The Mn–O–Mn angle of two adjacent MnO6 octahedra increases monotonically with increasing temperature. Based on these SXRD results, the local Jahn–Teller (JT) distortion of Mn sites within MnO6 octahedra of o-YMnO3 became suppressed, and the adjacent JT-distorted MnO6 octahedra became progressively symmetric with increasing temperature. The white-line profile of Mn \(K\)-edge spectra becomes more symmetric, originating from the suppression of the Jahn–Teller distortion of MnO6 octahedra ...