  The comprehensive search for multifunctional materials has resulted in the
discovery of semiconductors and oxides showing ferromagnetic features
persisting to room temperature. In this tutorial review the methods of
synthesis of these materials, as well as the application of element-specific
nano-analytic tools, particularly involving synchrotron radiation and electron
microscopy, are described and shown to reveal the presence of nano-scale phase
separations. Various means to control the aggregation of magnetic cations are
discussed together with the mechanisms accounting for ferromagnetism of either
condensed or diluted magnetic semiconductors. Finally, the question of whether
high temperature ferromagnetism is possible in semiconductors not containing
magnetic ions is touched upon.
