Spin fluctuations and alloying effects on low-temperature properties in BCC AxB1-xcompounds

A number of BCC alloys have been studied theoretically by self-consistent LMTO calculations using supercells of different sizes. To account for disorder effects a density-of-states broadening is used. Electron-phonon coupling, Stoner factors and superconducting transition temperatures have been calculated, including the effect of spin fluctuations. It is found that spin fluctuations are important for a good description of superconductivity. Moreover they can explain many experimental trends; in particular they show the increase of the transition temperature with pressure in NbZr compounds.