Superparamagnetic Behavior in an Amorphous Slag: 8CaO·8SiO₂·3Fe₂O₃·2FeO

Abstract

Amorphous insulating oxide 8CaO·8SiO₂·3Fe₂O₃·2FeO is prepared and its magnetization is measured in the temperature range 4.2K≤T≤798 K. The temperature- and field-dependences of the magnetization show that above about 50 K the sample is magnetically an aggregation of ferromagnetic fine particles (a superparamagnet) with paramagnetic ions and a small amount of crystalline Fe₃O₄ in gaps among them. The temperature- and field-dependences of the magnetization are analyzed by a simple model taking the superparamagnetism into account. The present slag is likely to enter into a mictomagnetic state around 50 K owing to magnetic interactions between the particles.