Magnetization and Resistivity Study of FCC $\gamma $-Fe Precipitates in Cu

Magnetization and resistivity measurements on two samples of Cu + 2.0 at.{\%} Fe are reported here. The first sample, prepared by annealing at 950 $^{o}$C for 2 days followed by rapid quenching, consists of a random solid solution of Fe in Cu. The magnetization follows the Curie-Weiss law 10 K $<$= T $<$= 300 K yielding an effective Fe moment of 1.9 $\mu _{B }$+/- 0.1 $\mu _{B}$ and Curie temperature of -- 2.0 K +/- 2.0 K. The second sample, prepared using the heat treatment above followed by a second annealing at 620 $^{o}$C for 2 hours, consists of face-centered-cubic $\gamma $-Fe precipitates in the Cu matrix. Evidence is given for an antiferromagnetic ordering occurring in this sample with a Neel temperature $\approx $ 55 K. The magnetization follows the Curie-Weiss law 100 K $<$= T $<$= 300 K yielding an effective Fe moment of 1.8 $\mu _{B}$ +/- 0.2 $\mu _{B}$ and a Curie temperature of -- 58 K +/--10 K. Resistivity measurements are also presented which assist in describing the structural nature and relevant magnetic interactions for these two samples.