Magnetoresistance of 5N, 6N, and 6N8 high purity aluminum

The electrical resistivity of high purity aluminum was measured in a magnetic field of up to 15 T in both the perpendicular and the parallel directions at 4.2 K with the four wire method. The effect of aluminum purity was investigated using wire specimens of three different purities, i.e., 5N and 6N-Al, which are commercially available, and 6N8-Al, which was further purified from 6N-Al. Specimens of commercial 5N copper were also tested for comparison. When a magnetic field was applied perpendicular to the current direction, RRR (residual resistivity ratio) declined with an increase in the field, with RRR at 15 T having a value that was about a third of that at 0 T. When the magnetic field was applied parallel to the current direction, RRR tended to show higher values than the former case, and the magnetoresistance behavior differed with the purity. While RRR of 5N-Al dropped sharply below 1 T and was almost constant over 1 T, RRR of 6N-Al and 6N8-Al increased with the magnetic field and maintained its hi...