1. Special Coordination of Materials Engineering, Federal University of Santa Catarina, Blumenau, Santa Catarina, Brazil
2. Department of Materials Engineering, LSQM – Laboratory of Chemical Synthesis of Materials, Federal University of Rio Grande do Norte, P. O. Box 1524, 59078-900, Natal, RN, Brazil
3. Department of Physics, Federal University of São Carlos, São Carlos, São Paulo, 13565-905, Brazil