Growth and optical properties of transition metal oxides single crystal solid solutions
Abstract NiO, CoO, MnO single crystals and single crystal solid solutions of Ni c Mg 1− c O, Co c Mg 1− c O and Mn c Mg 1− c O were grown by the method of chemical transport reaction (the “sandwich” technique). The nature of the observed absorption and luminescence bands is explained in terms of the electronic transition of bivalent nickel, cobalt and manganese. The fine structure of the observed bands in NiO and MnO are connected to the pure exciton transition and to the exciton-magnon excitation.
Raman and infrared spectromicroscopy of manganese oxides
Abstract Confocal micro-Raman and micro-FT-IR spectroscopies have been used to probe the phase composition of nominally pure single-crystal MnO and mixed MnO–Mn 3 O 4 samples, grown by the method of chemical transport reactions on MgO(1 0 0) substrate. The presence of spinel Mn 3 O 4 phase has been clearly detected in both samples by Raman and FT-IR spectroscopies. The size of the spinel Mn 3 O 4 phase regions has been estimated to be below 20 μm.
d-orbital theory for Mn2+-complex ions in crystals
The work is concerned with an ab initio calculation of the energy levels of Mn2+ ions in MnF2. The essential idea is the application of an analytic approximation of Watson's SCF procedure to obtain the spin-orbit interaction and the electrostatic parameters for the isolated ions. Crystal field energy levels are then calculated using the nearest-neighbour point-ion approximation. Despite these approximations the results are quite good and indicate that the technique may be of general use as the starting point of more sophisticated calculations on the dn ion in crystals. In addition, the bands at 39010 cm-1, 41340 cm-1 and 43200 cm-1 are interpreted in terms of double exciton transitions, which are in good agreement with experimental findings.