%0 Journal Article %J PHYSICAL REVIEW B %D 2005 %T Half-metallic ferromagnets for magnetic tunnel junctions by ab initio calculations %A P. Mavropoulos %A Lezaic, M. %A Blugel, S %X Using theoretical arguments, we show that, in order to exploit half-metallic ferromagnets in tunneling magnetoresistance (TMR) junctions, it is crucial to eliminate interface states at the Fermi level within the half-metallic gap; contrary to this, no such problem arises in giant magnetoresistance elements. Moreover, based on an a priori understanding of the electronic structure, we propose an antiferromagnetically coupled TMR element based on half-metallic zinc-blende chalcogenides, in which interface states are eliminated, as a paradigm of materials design from first principles. Our conclusions are supported by ab initio calculations. %B PHYSICAL REVIEW B %V 72 %P 174428 %8 NOV %G eng %R 10.1103/PhysRevB.72.174428