Structural and magneto-transport characterization of Co_2Cr_xFe_(1-x)Al Heusler alloy films

摘要

We investigate the structure and magneto-transport properties of thin filmsof the Co_2Cr_xFe_(1-x)Al full-Heusler compound, which is predicted to be ahalf-metal by first-principles theoretical calculations. Thin films aredeposited by magnetron sputtering at room temperature on various substrates inorder to tune the growth from polycrystalline on thermally oxidized Sisubstrates to highly textured and even epitaxial on MgO(001) substrates,respectively. Our Heusler films are magnetically very soft and ferromagneticwith Curie temperatures up to 630 K. The total magnetic moment is reducedcompared to the theoretical bulk value, but still comparable to values reportedfor films grown at elevated temperature. Polycrystalline Heusler films combinedwith MgO barriers are incorporated into magnetic tunnel junctions and yield 37%magnetoresistance at room temperature.