Institute for Materials Research, Tohoku University
There are many exotic superconductors which contains uranium atom. This is due to the characteristic properties of 5f electrons in uranium atom, which show the dual nature (itinerant and localized) and the strong spin-orbit coupling. For instance, the microscopic coexistence of ferromagnetism and superconductivity is known in uranium compounds, though they are usually antagonistic on the basis of the conventional BCS theory. The spin-triplet superconductivity is realized with the ferromagnetic fluctuations as a “glue” of superconducting pairing.
In this talk I will present an overview of ferromagnetic superconductivity and the spin-triplet state in uranium compounds. In particular, I will focus on the new spin-triplet superconductor UTe2 and its pressure and field response. A spectacular field-reentrant superconductivity, multiple superconducting phases, and the pressure-induced magnetism are reported in UTe2. I will further present our recent results and perspectives on UTe2.