Single magnetic domain precipitates of Fe/Co and Fe and Co in Cu matrix produced from (Fe-Co)/Cu metastable alloys

Structural and magnetic properties of nanocrystalline Fe2Co and (Fe2Co)(0.3 0) Cu-0.70 alloys prepared by high energy ball milling have been studied ba sically by x-ray, Mossbauer spectroscopy and magnetization measurements. Fo r the Fe2Co alloy case, the Mossbauer measurements indicate that the sample with 160 hours of milling has two magnetic components with the same averag e hyperfine parameters: one magnetic crystalline component associated with the bcc Fe2Co phase and another component attributed to the small particles of the same bcc Fe2Co phase (SP-Fe2Co). (Fe2Co)(0.30)Cu-0.70 alloys have b een prepared by milling in two different ways: (I) starting from the mixtur e of Fe2Co milled alloy and pure Cu powders (sample I);Ind (2) milling of t he elemental powder mixture of Fe, Co and Cu (sample II). The x-ray diffrac tion and bulk magnetization results of samples I and II indicate the format ion of a (Fe2Co)(0.30)Cu-0.70 supersaturated solid solution, with features of a ferromagnetic material and T-c at about (420 +/- 1) K. High temperatur e magnetization measurements of the (Fe/Co)Cu milled materials show particl e precipitation effects. Heat treatment at 675 and 875 K of the final mille d materials leads to different results: in the sample I case to the precipi tation of single magnetic Fe/Co particles into the Cu matrix, and in the ca se of sample II the precipitation of single magnetic particles of Fe and of Co into the Cu matrix.