Magnetic study of Fe65Ni20Nb6B9 nanocomposite alloys

A.F. CABRERA; CLAUDIA E. RODRÍGUEZ TORRES; P. MENDOZA ZÉLIS; L. SOCOLOVSKY; M. B. FERNÁNDEZ VAN RAAP; G. PASQUEVICH; F. H SÁNCHEZ

PHYSICA B - CONDENSED MATTER

Año: 2004 vol. 354 p. 129 - 133

0921-4526

The alloy Fe65Ni20Nb6B9 was obtained from the elemental constituents in a high-energy planetary ball mill and subsequently thermally treated at 873 and 900K in order to obtain the equilibrium phases. The as-prepared nanocrystalline alloy consists primarily of metastable BCC a-Fe(Ni) nanocrystals while the treated ones consist of a mixture of BCC (ferromagnetic) and FCC (paramagnetic at room temperature) phases. Hysteresis loops at 5 and 300K present low remanence and coercivity. As-prepared sample exhibits the best soft magnetic properties. In all samples, the susceptibility curves suggest magnetic collective (long-range order) behavior with a maximum between 70 and 90 K. This feature is caused by nanometric-sized magnetic particles. The huge difference between blocking and irreversibility temperatures in the .eld cooling and zero field cooling scans indicates a wide grain-size distribution.