Effect of composition on phase formation and magnetic properties of highly coercive Sm–Co films

Abstract Highly textured Sm–Co films with varying Sm content have been prepared using pulsed laser deposition. The films have been deposited on single crystalline MgO (0 0 1) substrates with a Cr buffer and Cr protection layer. The composition of the Sm–Co films ranges from Sm14.5Co85.5 to Sm23Co77 and the effect of composition on the phase formation, texture and magnetic properties has been studied. In all films the c-axis, which is the easy magnetization axis, lies in the film plane. This is observed by means of X-ray diffraction in θ – 2 θ geometry, which shows predominantly (1 1 0) reflections, and by means of magnetic measurements, which show a strong anisotropic behavior. Reducing the Sm content leads to a continuous shift in the Sm–Co (1 1 0) peak position, indicating a gradual compression of the crystal lattice. The saturation polarization and hence the remanent polarization in the film plane increases significantly as the Sm content is reduced to 14.5 at%. These Co-rich films possess texture and coercivity values similar to epitaxial Sm22Co78 films, but with largely improved polarization.