Probing Dy3+ magnetic moments in multiferroic perovskite DyMnO3 by optical spectroscopy

We present a detailed temperature-dependent (4-300 K) spectroscopic study of DyMnO3 single crystals with distorted perovskite structure. Energies of 36 crystal-field levels of Dy3+ in paramagnetic DyMnO3 were determined. The Dy3+ ground Kramers doublet does not split at T-N(mN) = 39 K and splits below T-lock = 18 K. The splitting grows fast at temperatures near T-N(Dy) = 6.5 K and reaches Delta(0) approximate to 11 +/- 2 cm(-1) at 4 K. Using the experimental temperature dependence Delta(0)(T), we calculate the dysprosium magnetic moment m(Dy)(T) and the dysprosium contribution into specific heat and magnetic susceptibility. Analysing all the experimental data, we conclude that the Dy-Mn interaction is of the Dzyaloshinskii-Moriya type. [GRAPHICS] Intensity map in the temperature-wave number coordinates for a spectral line corresponding to the f-f transition of Dy3+ in DyMnO3 and a scheme of the splitting of the Dy ground Kramers doublet. Arrows represent Dy magnetic moments. (C) 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim