1. Magnetic Materials and Nanostructures Group, Phys. Dep., Universidad Nacional de Colombia, Carrera 45 No 26-85, Bogotá, Colombia
2. Excellence Center for Novel Materials, CENM, Calle 13 N.100-00 Building 320 ofice 1030, Cali, Colombia
3. Physics Department, Universidad Nacional de Colombia, Carrera 45 No 26-85, Bogotá, Colombia