1. Post‐Graduate Program in Materials Science and Engineering Federal University of Pelotas Pelotas Rio Grande do Sul Brazil
2. Post‐Graduate Program in Physics Federal University of Pelotas Capão do Leão Rio Grande do Sul Brazil
3. Spectroscopy Laboratory Federal University of Pampa Bagé Rio Grande do Sul Brazil
4. Post‐Graduate Program in Materials Science and Technology São Paulo State University Bauru São Paulo Brazil
5. Department of Physics São Paulo State University Bauru São Paulo Brazil