[1] Univ Buenos Aires, Fac Ingn, INTECIN, Lab Solidos Amorfos, Buenos Aires, DF, Argentina
[2] Univ Fed Goias, Inst Fis, BR-74001970 Goiania, Go, Brazil
[3] Univ Nacl Autonoma Mexico, Fac Quim, Dept Fis & Quim Teor, Mexico City 04510, DF, Mexico
[4] Univ Sao Paulo, Inst Fis, Lab Mat Magnet & Espect Mossbauer, BR-01498 Sao Paulo, Brazil
[5] Univ La Habana, Inst Mat & React, Havana, Cuba