  Thin Co-Mn-Sb films of different compositions were investigated and utilized
as electrodes in alumina based magnetic tunnel junctions with CoFe counter
electrode. The preparation conditions were optimized with respect to magnetic
and structural properties. The Co-Mn-Sb/Al-O interface was analyzed by X-ray
absorption spectroscopy and magnetic circular dichroism with particular focus
on the element-specific magnetic moments. Co-Mn-Sb crystallizes in different
complex cubic structures depending on its composition. The magnetic moments of
Co and Mn are ferromagnetically coupled in all cases. A tunnel magneto
resistance ratio of up to 24 % at 13K was found and indicates that Co-Mn-Sb is
not a ferromagnetic half-metal. These results are compared to recent works on
the structure and predictions of the electronic properties.
