Following the discovery that a class of layered iron arsenides become superconducting above 40K, the air has been heavy with the boiling and smelting of new compounds that might also behave in this way.
The trick is to find a compound that mimics the structure of the iron arsenides in question. These have a tetragonal crystal structure in which layers of lanthanum oxide are sandwiched between layers of iron arsenide.
But another significant point is that within the family of arsenides, the iron compound is on the border of a magnetic instability, say Victor Kozhevnikov from the Institute for Solid State Chemistry in Yekaterinburg, Russia and colleagues.
This group has found another substance that exactly matches these two properties. It’s an oxybismuthide in which tetragonal layers of lanthanum oxide are sandwiched between layers of nickel bismuthide and which also sits on the border of a magnetic instability relative to related compounds.
Kozhevnikov and his buddies have even made LaONiBi and say it superconducts at 4K, which is where the iron arsenides started off a couple of years ago.
If the oxybismuthides follow the same trajectory, a few choice substitutions should see them superconducting at 40K plus.
Exciting times in the world of superconductivity .
Ref: arxiv.org/abs/0804.4546: New Enlargement of the Novel Class of Superconductors