No abstract

The orthorhombic rare-earth manganite compounds RMnO 3 show a global magnetic order for < T T N , and several representatives are multiferroic with a cycloidal spin ground state order for. We deduce from the temperature dependence of spin-phonon coupling in Raman spectroscopy for a series of RMnO 3 compounds that their spin order locally persists up to about twice T N . Along the same line, our observation of the persistence of the electromagnon in GdMnO 3 up to » T 100 K is attributed to a local cycloidal spin order for > T T cycl , in contrast to the hitherto assumed incommensurate sinusoidal phase in the intermediate temperature range. The development of the magnetization pattern can be described in terms of an order-disorder transition at T cycl within a pseudospin model of localized spin cycloids with opposite chirality.-Eu x 1 Y x MnO 3 or

We report the observation of tens of minor lines of the combinational spin-flip Raman scattering in aCdTe:Mn quantum well by means of the high-resolution optical spectroscopy. Classification of this manifold leads to four characteristic values of energy, that correspond to four different types of pair clusters of Mn ions: the nearest, second, third etc. neighbors. All the four energies show up in a single experiment with a very high precision, providing experimental grounds for a deeper understanding of the d-d exchange interactions in a diluted magnetic semiconductor and demonstrating the capacity of the employed method. Notably, the major nearest-neighbor exchange constant