1. Brazilian Nanotechnology National Laboratory (LNNano), Brazilian Center for Research in Energy and Materials (CNPEM), 13083-970 Campinas, São Paulo, Brazil
2. Postgraduate Program in Materials Science and Technology (POSMAT), São Paulo State University (UNESP), 17033-360 Bauru, São Paulo, Brazil
3. Department of Physics (CCET), Federal University of Maranhão (UFMA), 65080-805 São Luís, Maranhão, Brazil