Electronic structure and magnetic symmetry in MnTiO sub(3) analyzed by second harmonic generation

Second harmonic generation (SHG) and linear absorbance spectra of MnTiO sub(3) were measured and the 1.88, 2.41, 2.63, and 3.06 eV SHG features were identified as d - d optical transitions from super(6) A sub(1g) to super(4)T sub(1g)( super(4)G), super(4)T sub(2g)( super(4)G), { super(4)E sub(g), super(4)A sub(1g)( super(4)G)}, and super(4)E sub(g)( super(4)D), respectively. These zero-phonon transitions were used to calculate the octahedral crystal field splitting energy ( Delta sub(0)) and the Racah parameters B and C. The SHG spectra showed significant distinctions between the antiferromagnetic and the paramagnetic or spin-flop phases. The polarization dependence of the SHG in the spin-flop phase provided optical evidence that the spins canted from the c axis toward the a axis. These distinctions between the three magnetic phases could be useful for mapping 180[degrees] antiferromagnetic domains in MnTiO sub(3).