1. a PRINSO: Program of Research in Solid State Physics of CONICET(National Council for Scientific and Technological Research) , Zufriategui 4380, (1603) Villa Martelli, Pcia , Buenos Aires , Republica Argentina
2. b PRINSO: Program of Research in Solid State Physics of CITEFA(Institute for Scientific and Technological Research of the Army Forces) , Zufriategui 4380, (1603) Villa Martelli, Pcia , Buenos Aires , Republica Argentina