Mössbauer and magnetic studies of nanosize (Fe,Co) _x C _1∈-∈x alloys

Nanosize Fe _x C_1∈-∈x and (Fe,Co) _x C_1∈-∈x alloys were synthesized by a low-temperature pyrolysis technique. Room temperature magnetization studies of Fe _x C_1∈-∈x alloys show linear magnetic field dependence. On the other hand, the M(H) curves of the mixed (Fe,Co) _x C_1∈-∈x alloys, exhibit a clear ferromagnetic behavior. Moreover, the saturated magnetic moments obtained (at H>10 kOe), exceed that of bulk iron, which reminiscences the dilute magnetic semiconducting materials. Mössbauer spectroscopy studies of Fe _x C _1∈-∈x alloys show the existence of Fe₂O ₃ as the major fraction of the samples. On the other hand, for the (Fe,Co) _x C_1∈-∈x samples, a well defined sextet which corresponds to Fe metal is observed. Moreover, the effective magnetic hyperfine field (H _eff) value is 380 kOe much larger than that of bulk Fe (H _eff = 330 kOe). It is concluded that in the mixed (Fe,Co) _x C_1∈-∈x materials, Fe-Co alloys are formed and their higher M _S and H _eff values are explained in terms of the Slater-Pauling plots.