Nonlinear optical spectroscopy of electronic transitions in hexagonal manganites

The hexagonal rare-earth manganites RMnO₃ (R = Sc, Y, Ho, Er, Tm, Yb, Lu) are a group of materials with an unusual combination of magnetic, electric and optical properties. The electronic structure of these materials was studied by second harmonic (SH) spectroscopy in the range from 1.2 to 3.0 eV. Faraday rotation and absorption spectra were measured in the range from 1.0 to 1.6 eV. Broad bands at ∼1.7 eV and ∼2.7 eV are assigned to electronic transitions between Mn³⁺(3d⁴) levels. The SH spectra are discussed on the basis of a recently developed microscopic theory. Received: 26 April 2001 / Published online: 18 July 2001