REMANENT MAGNETIZATION OF COO.A12O3.SIO2 GLASS - 1OG T LAW

Cobalt and manganese aluminosilicate glasses have magnetic properties very similar to those of spin-glass alloys, demonstrating that spin-glass ordering is not restricted to RKKY coupled spins. In the present paper we report long-time relaxation effects observed in the remanent magnetization of a 33.5 at.% Co-aluminosilicate glass (composition 83.1 mole% CoO, 15.5 mole% Al 2O3, 1.4 mole% SiO2). Such effects have also been seen recently in the spin-glass alloy AuFe by Guy and by Nieuwenhuys and Mydosh. As in the case of the alloy, the remanent magnetization follows a logt law. This behavior will be discussed in terms of a superparamagnetic blocking model.