Collisional Stability of K-40 Immersed in a Strongly Interacting Fermi Gas of Li-6

We investigate the collisional stability of a sample of K-40 atoms immersed in a tunable spin mixture of Li-6 atoms. In this three-component Fermi-Fermi mixture, we find very low loss rates in a wide range of interactions as long as molecule formation of Li-6 is avoided. The stable fermionic mixture with two resonantly interacting spin states of one species together with another species is a promising system for a broad variety of phenomena in few- and many-body quantum physics.