Magnetic behavior of Co clusters embedded in a zeolite matrix

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

Buenos Aires, Argentina

Workshop; Recent Developments in Complex Materials: Production and Characterization; 2005

A medium pore zeolitic material with MFI structure modified with Co cations was synthesized. The magnetization M and magnetic susceptibility ÷ were measured as a function of T after ZFC and as function of the applied magnetic field fot T between 4.2 and 30 K. No blocking temperature was detected and a pure superparamagnetic behavior was obtained. M vs. T and ÷ vs.T curves were adjusted by Brilloin and Langevin functions obtaining the same results in both cases. Curve fitting gave an effective moment of ~ 90 µB for the cases under study. The results are analyzed in terms of the possible clusters structure that may appear.