Modelling the irreversible response of nanoscale magnetite: Two competing Preisach scenarios

We present a comprehensive experimental characterization of the field and temperature and time dependence of the magnetic response of a powder of nanoscale magnetite particles. The data are analyzed within the framework of the Preisach formalism, and numerical simulations of the field-cooled moment, the zero field-cooled moment, the thermoremanent moment and the isothermal remanent moment, based on two extreme physical scenarios, are compared.