We describe the growth and properties of (ln(0.5)Al(0.5))(1-x) MnxAs and (ln(0.5)Ga(0.5))(1-x)MnxAs epilayers and superlattices. We find that the structural quality of the epilayers is similar to that of the more extensively studied ln(1-x)Mn(x)As and Ga1-xMnxAs magnetic semiconductors and that we can incorporate significantly larger amounts of Mn (similar to 12 %) without phase segregation. Magnetization measurements indicate that the Curie temperatures of (ln(0.5)Ga(0.5))(1-x)MnxAs and (In0.5Al0.5)(1-x)MnxxAs (x similar to 0.11) epilayers are 95 and 25 K, respectively. The Curie temperature of the (In0.5Ga0.5)(1-x)MnxAs/(In0.5Al0.5)(1-x)MnxAs superlattices decreases with the increase of the Al/(Al+Ga) ratio. We attribute this to a decreased overlap between the impurity band and the valence band because of an enhanced Mn acceptor activation energy. (c) 2005 American Vacuum Society.