Magnetic behavior of Co clusters embedded in a zeolite matrix

H. R. BERTORELLO; L. B. PIERELLA; P. G. BERCOFF; C. SAUX; J. P. SINNECKER

PHYSICA B - CONDENSED MATTER

Año: 2004 vol. 354 p. 137 - 140

0921-4526

A medium pore zeolitic material with MFI structure modified with Co cations was synthesized. The magnetization M and magnetic susceptibility w were measured as a function of T after ZFC and as a function of the applied magnetic field for T between 4:2 and 30 K. No blocking temperature was detected and a pure superparamagnetic behavior was obtained. M vs. T and w vs. T were adjusted by Brillouin and Langevin functions obtaining the same results in both cases. Curve fitting gave an effective moment of ~90mB for the cases under study. The results are analyzed in terms of the possible cluster structure that may appear.