A Preisach analysis of superparamagnetism in thin-film granular Fe-SiO2

Measurements of the field-cooled and zero-field-cooled moment and of the ma jor hysteresis loop have been performed on a sample of thin-film granular F e-SiO2 over a wide range of temperatures (2 K less than or equal to T less than or equal to 300 K) and in magnetic fields between -2500 Oe less than o r equal to H-a less than or equal to + 2500 Oe. The data were analyzed with in the framework of a recently developed Preisach model for superparamagnet ism in magnetically ordered materials. (C) 2001 Elsevier Science B.V. All r ights reserved.