ISSN:
1089-7550
Source:
AIP Digital Archive
Topics:
Physics
Notes:
Magnetoresistance (MR) measurements on four film samples of the ternary alloy CuNiCo were performed at room temperature in fields H≤20 kOe. Following growth by sputtering onto thermally oxidized Si substrates, the films (100–200 nm thick) were annealed between 1 and 6 h at temperatures TA=200, 350, 500, and 700 °C. The samples display anisotropic magnetoresistances (AMR) for H〈100 Oe of up to 3% at room temperature for Cu20Ni53Co27 (TA=350 °C). Despite the fact that in the bulk these alloys tend to phase separate into Co rich and Co poor regions, we find evidence for giant magnetoresistance (i.e., an isotopic negative component to the MR) in only one sample, Cu51Ni17Co31, after a 6 h, 700 °C anneal. In the as-deposited condition, samples Cu20Ni53Co27 and Cu13N41Co46 display a pronounced asymmetry between the resistance decrease for H applied perpendicular to the current I and the corresponding increase for H parallel to I which substantially exceeds the 1:2 ratio in bulk materials or the 1:1 ratio expected for a thin film. The large observed values of AMR (more evident in samples with low Cu concentrations) are likely linked to AMR in binary CuCo alloys, which are known to exhibit large AMR. The disparity between the MR for H parallel and perpendicular to the current we attribute to magnetic anisotropy induced during fabrication.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.358324
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