Enhanced exchange bias coupling in Fe∕FexMn1−x bilayer by reducing vertical lattice constants

The modification of crystalline structure by epitaxial growth on different single crystals induces crucial effects on the exchange bias coupling. Due to the larger lattice constant (a0) of Cu3Au(100) (a0=3.75A), the vertical lattice constants of Fe∕FexMn1−x films on Cu3Au(100) are much smaller than those of the Fe∕FexMn1−x∕Cu(100) system (Cu: a0=3.61A). By reducing the vertical lattice constants, the interface exchange bias coupling energy of Fe∕FexMn1−x∕Cu3Au(100) is enhanced to be 0.12–0.18erg∕cm2, which is approximately four times that of the Cu(100) system.