Synthesis and characterization of RBaCo2O5+x (R La, Nd, Gd, y and Ho)

Abstract

Ceramics of double perovskite RBaCo2O5+x (R La, Nd, Gd, Y and Ho) were prepared in air at diferent annealing conditions. The samples were characterized by optical microscopy, X-ray powder difraction, scanning electron microscopy (SEM), energy-dispersive X-ray analysis (EDX), and micro-Raman spectroscopy. In the case of RBaCo2O5+x (R Gd, Y and Ho) the optical anisotropy of the tetragonal-like microcrystals observed is sufcient to determine their orientation and to obtain their polarized Raman spectra from (001)- and (100)-type oriented crystal surfaces. Due to the fact that some of the impurities observed in the ceramics have Raman spectra with intensity much larger compared to that of the main phase, special attention was paid to identify their Raman spectra. The origin of the lines observed in the polarized Raman spectra of RBaCo2O5+x phase (R Gd, Y and Ho) is discussed. © 2010 IOP Publishing Ltd.