Superconductivity of ε-Fe: complete resistive transition

• Published in: Physics letters. A Vol. 299; no. 2; pp. 282 - 286
• Main Authors: Jaccard, D, Holmes, A.T, Behr, G, Inada, Y, Onuki, Y
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01-07-2002
• Subjects: Electrical resistivity; High pressure; Iron; Superconductivity; 74.70.-b; Iron; Electrical resistivity; 62.50; Superconductivity; High pressure
• ISSN: 0375-9601; 1873-2429
• DOI: 10.1016/S0375-9601(02)00725-9

Last year, iron was reported to become superconducting at temperatures below 2 K and pressures between 15 and 30 GPa, Nature 412 (2001) 316. The evidence presented was a weak resistivity drop, suppressed by a magnetic field above 0.2 T, and a small Meissner signal. However, a compelling demonstration, such as the occurrence of zero resistance, was lacking. Here we report the measurement of a complete resistive transition at 22.2 GPa with an onset slightly above 2 K in two very pure samples of iron, of different origins. The superconductivity appears unusually sensitive to disorder, developing only when the electronic mean free path is above a threshold value, while the normal state resistivity is characteristic of a nearly ferromagnetic metal.