Magnetic ordering in Mn-doped KTaO3 was investigated as a function of Mn-content and processing route. Although we have detected the antiferromagnetic ordering at low temperature (42K) we showed that its origin is not in intrinsic long-range nor spin-glass ordering of Mn spins in the KTaO3 host lattice as often claimed in literature. We present evidences that the ordering is of an extrinsic nature and originates from traces of residual Mn3O4 not incorporated into the KTaO3 matrix.
COBISS.SI-ID: 1422075
We reported on discovery of a new pyrochlore compound, (Bi1.88Fe0.12)(Fe1.42Te0.58)O6.87, which is characterized by the highest Fe content among all known pyrochlores. using x-ray and neutron diffraction we determined its crystallographic properties. At 20K the pyrochlore developed strong spin coupling into the spin glass state. At tis temperature the influence of the magnetic coupling on dielektrik properties was shown, which confirms the magnetoelectric coupling.
COBISS.SI-ID: 1894907
SrTiO3 is considered to be one of the most interesting quantum paraelectrics, which ferroelectric state can be induced by doping. We have paid special attention to the influence of doping with paramagnetic ions Mn2+ and Mn4+ on the magnetic properties. Within this study we have investigated in details the incorporation mechanisms of dopants; among them Mn. The study resulted in some surprising results on influence of the processing parameters on the atomistic mechanisms of the incorporation and the absence of magnetization in the case of an ideal dopant incorporation. This contradicts and disproves current theories on local fields in this material and, therefore, our work has attracted huge interest and was published in such respected journal as Advanced Functional Materials is.
COBISS.SI-ID: 2265083
We reported photoemission experiments revealing the full valence electron spectral function of Ce adatoms on Ag(111), W(110), and Rh(111) surfaces. A transfer of Ce 4f spectral weight from the ionization peak towards the Fermi level is demonstrated upon changing the substrate from Ag(111) to Rh(111). In the intermediate case of Ce on W(110) the ionization peak is found to be split. This evolution of the spectra is explained by means of first-principles theory, which clearly demonstrates that a reliable understanding of magnetic adatoms on metal surfaces requires simultaneous low and high energy spectroscopic information.
COBISS.SI-ID: 1968635
We have experimentally investigated the synthesis of BiVO3 perovskite. We identified the solid-state redox reaction as a process that averts the formation of BiVO3. At elevated temperatures, Bi3+ oxidizes V3+ to yield metallic Bi and V5+ species. This process prevails over the formation of BiVO3. The BiVO3 perovskite structure requires a strong orbital coupling between Bi3+ and VO6 octahedra but this facilitates the electron transfer between V3+ and Bi3+. At the investigated temperatures ()400 °C), the activation energy for the electron transfer from V to Bi is exceeded and the structure is destabilized, but the synthesis of BiVO3 might be possible at lower temperatures for which the activation energy for the redox reaction is not exceeded.
COBISS.SI-ID: 21319398