Experimental study of the spin density of metastable fcc ferromagnetic Fe-Cu alloys

Magnetization density measurements on metastable FexCu1-x alloys at four compositions (x = 20, 40, 50, and 60 at. %) and at 5 K temperature were carried out by means of polarized neutron diffraction. The samples were produced by high-energy ball milling and characterized by x-ray diffraction and fluorescence measurements. Additional bulk magnetization measurements were carried out on the two samples at high Fe concentration. Over the present concentration region, the Fe-Cu system is ferromagnetic and the four samples were found to be in the fcc phase. Fe-Cu is therefore a very suitable system to investigate the magnetic state of Fe in an fee environment. Other than confirming that the Fe-Cu system is not a simple dilution alloy, the present results were compatible with a two-state model for fee Fe-that is, two different coexisting electronic states associated with different magnetic moments and form factors.