Magnetic, resistive and magnetoresistive properties of melt spun CoCu alloys

Abstract Co 10 Cu 90 alloys were prepared by melt spinning in a twin roller device at 5 m/s and 23 m/s tangential wheel velocities. The low temperature (5–300 K) magnetic and electron transport properties were investigated in as cast alloys and in samples annealed for 1 h at 923 K. Magnetoresistance (MR) measurements were performed between 35 K and 295 K, with applied field up to 0.85 T. For each condition, M–H loops and M(T) curves were measured and analyzed to estimate the mean Co particle size and the blocking temperature distribution, respectively. In the as cast condition, particle sizes between 2.3 nm and 5.7 nm and mean blocking temperatures between 31 K and 247 K are found; these alloys, cooled at these relatively low rates, show appreciable room temperature MR values (0.5–1.5% for 0.85 T). A minimum resistance is found at about 30 K in alloys with compositions up to 15 at% Co.