1. Department of Physics, National Dong Hwa University, Hualien 97401, Taiwan
2. Functional Materials Development Center (CDMF), Federal University of São Carlos─UFSCar, 13565-905 São Carlos, São Paulo, Brazil
3. Department of Natural and Earth Sciences, Minas Gerais State University─UEMG, 35501-170 Divinópolis, Minas Gerais, Brazil
4. Prof. C.N.R. Rao Centre for Advanced Materials, Tumkur University, Tumkur 572103, India