Abstract
The element osmium (Os), with high melting and boiling points, plays a crucial role in the development of the L1 0 order for FePt in [Os(5 nm)/FePt(25 nm)] 4 and [Os(1 nm)/FePt(5 nm)] 20 systems. The large mismatches of lattice constants between Os and FePt, with specific epitaxial relations, induce a great strain in the [Os(5 nm) /FePt(25 nm)] 4 system with fixed total thicknesses for the FePt and Os layers. Due to this large strain effect, the L1 0 order in a FePt structure can be enhanced through an application of stressing along the c axis for the face-centered cubic structure, which results in a higher coercivity. However, a smaller degree of average strain was observed in the 5 nm-thickness FePt system due to the existence of pinholes. © 2013 AIP Publishing LLC.