Preparation and magnetic properties of colloidal ferromagnetic metals

Abstract Stable magnetic fluids containing fine particles of Fe, Co or Ni have been prepared by evaporating the metals in vacuum onto the surface of the oil containing an oil-soluble surfactant. At room temperature, these magnetic fluids are superparamagnetic and have saturation magnetizations of 165, 270 and 84 G for the Fe, Co and Ni magnetic fluids, respectively.