A superconducting ferromagnet at normal pressure has been devised from the elements uranium, cobalt, and germanium by physicists from the University of Amsterdam and the University of Karlsruhe. Normally magnetism is anathema to the delicate pairing of electrons at the heart of the superconducting phenomenon.
This would be especially true for ferromagnetism, that sturdiest of magnetic states (in which atoms aligned by an external magnet retain their coordination even when the external field is removed). A few years ago several materials were found that supported superconductivity and ferromagnetism, but only under conditions of high pressure or extremely cold temperatures (see Physics Today, Sept 2001).
What happens is that instead of the normal pairing of two electrons with opposite spins (one spin up and one spin down-a “spin-singlet” state) in these ferromagnetic-tolerant materials the pairings involve electrons whose spins are in the same direction (a spin-triplet state). The material remains superconducting and ferromagnetic both under ordinary pressures, and at a temperature, 1 K, about four times higher than for any other ambient-pressure material.
According to one of the researchers, Anne de Visser (firstname.lastname@example.org), the presence of the magnetic fluctuations needed to preserve the ferromagnetic state might complicate, in an interesting way, the BCS mechanism normally at work in low-temperature superconductors. (Huy et al., Physical Review Letters, upcoming article; lab website, http://www.science.uva.nl/research/cmp/devisser/)