Magnetic study of particle distribution in granular AuCo

Abstract Measurements of field-cooled magnetization (FCM) and reversed-field-cooled magnetization (RFCM) in granular Au 0.82 Co 0.18 films were carried out at various applied magnetic fields. It is shown that temperature derivatives of the difference between FCM and RFCM provide information on size distribution of the superparamagnetic Co particles. The field dependence of the blocking temperatures, obtained by the same measurements, is found to deviate from existing theories.