EPR study of Mn²⁺ in ferroelastic BiVO₄ single crystal: Monoclinic spin hamiltonian parameters and their temperature dependence

Abstract

Zero-field splitting (ZFS) parameters of Mn²⁺ in a BiVO₄ single crystal obtained with a Q-band EPR spectrometer at room temperature are analyzed with the monoclinic spin Hamiltonian and compared with those of Baran et al. The ZFS B_k ^q shows that the site symmetry of Mn²⁺ (or Bi³⁺) center in the ferroelastic BiVO₄ crystal is monoclinic. The temperature dependence of Mn²⁺ spectrum in BiVO₄ is investigated in the X-band over the temperature range 3.8 K to 291 K. The axial ZFS parameter B₂ ⁰ for Mn²⁺ center increases with decreasing temperature and saturates at below 30 K, while B₂ ² is nearly constant below 300 K.