  High-quality layers of the (Ga,Mn)(Bi,As) quaternary compound semiconductor
have been grown by the low-temperature molecular-beam epitaxy technique. An
effect of Bi incorporation into the (Ga,Mn)As ferromagnetic semiconductor and
the post-growth annealing treatment of the layers have been investigated
through examination of their magnetic and magneto-transport properties.
Significant enhancement of the planar Hall effect magnitude upon addition of Bi
into the layers is interpreted as a result of increased spin-orbit coupling in
the (Ga,Mn)(Bi,As) layers.
