Probing itinerant ferromagnetism with a ferromagnet/insulator/superconductor junction

A ferromagnet/insulator/superconductor ballistic junction is used to distinguish the contributions due to exchange splitting and spin-dependent mass renormalization of up- and down-spin bands in itinerant ferromagnets. The study is performed within the Blonder-Tinkham-Klapwijk approach and by solving the corresponding Bogoliubov-de Gennes equations in a way to get the current flux across the junction. The averaged differential conductance is shown to exhibit features that depend on the strength of the mass and the exchange splitting while the knowledge of the transmission critical angle provides a mean to measure the mass asymmetry among up and down carriers.