[1] Univ Nacl Tucuman, Lab Fis Solido, Dept Fis, Fac Ciencias Exactas & Tecnol,CONICET, San Miguel De Tucuman, Argentina
[2] Univ Buenos Aires, Fac Ingn, Dept Fis, Lab Ablac Laser, Buenos Aires, DF, Argentina
[3] Univ Nacl La Plata, Dept Fis IFLP, Fac Ciencias Exactas, La Plata, Buenos Aires, Argentina
[4] Univ Leipzig, Div Superconduct & Magnetism, Inst Expt Phys 2, Leipzig, Germany