Unconventional drop in the electrical resistance of chromium metal thin films at low temperature

• The electrical resistance measurements were performed in several chromium films.
• We observed sudden decrease in the resistance around 1.5 K, but the electrical resistivity is not zero in all films.
• It is difficult to conclude whether a superconducting transition occurs contrary to the previous reports.

We studied the electrical resistance of single-crystal and polycrystalline chromium films. The ρ(T)ρ(T) curve of single-crystal films decrease with decreasing temperature and show humps at around 300 K consistent with the bulk chromium being an itinerant antiferromagnet. In the polycrystalline films, on the other hand, the ρ(T)ρ(T) curves deviate from those of the bulk chromium. Moreover, we observed sudden decrease in the resistance around 1.5 K. Although previous studies suggested that chromium films become superconductive (Schmidt et al. (1972) [12]), it is difficult to conclude whether a superconducting transition occurs because the electrical resistivity is not zero in all films. No anomaly was detected by resistance measurements around room temperature, and the sudden decrease in the resistance at low temperature may be attributed to the suppression of antiferromagnetic interaction by thinning down the chromium element.