Nonlinear optics as a novel tool for studying magnetic crystals

We show that by analysing nonlinear spectra of second-harmonic generation w e can confirm magnetic structures known from other experiments or distingui sh magnetic structures which cannot be distinguished by neutron diffraction or other experiments. Experimental data for the hexagonal rare-earth manga nite HoMnO3 are presented. (C) 2000 Elsevier Science B.V. All rights reserv ed.