Resonance Raman spectroscopy of NdAlO3 single-crystal fibers grown by the laser-heated pedestal growth technique

NdAlO3 is a lanthanide monoaluminate compound presenting a trigonal structure with D3d6 space group. Single crystal fibers of NdAlO3 were grown by the laser-heated pedestal growth (LHPG) technique. The cylindrical fibers grew parallel to [1 0 0]h direction without cracks or striations. At room temperature, the Raman spectra presented an enlarged number of the measured bands. Raman bands associated to the D3d6 structure were compared with the prediction of lattice dynamic calculations performed using Wilson's GF-matrix method. By using group-theory calculations, it was possible to suggest a reduction in crystal symmetry induced by the Nd/Al non-stoichiometric ratio. The C3v6 and S62 phases are the best choices to describe the unit cell of our Al-deficient crystal fiber in place of D3d6 phase.