Lattice distortion and magnetic properties of nanometer size Fe(1 1 0) islands

Epitaxial Fe(1 1 0) islands of nanometric dimensions have been obtained on c-sapphire by triode sputtering. By ex situ X-ray diffraction (XRD) measurements we observe a strong dependence of the perpendicular lattice parameter as a function of the vertical island size and the deposition geometry. Deposition with the substrate facing the Fe target gives rise to almost relaxed islands. However, deposition with the substrate facing opposite to the Fe target yields to highly distorted islands (up to 5% along the growth direction). XRD rocking scans show two components in k parallel: a narrow one, independent of the island dimension, that it is correlated to the Fe/sapphire interface, and a broad one, related to its in-plane disorder, the width of which decreases when the island lateral dimension is increased. Correlation of the structural changes with the magnetization reversal processes and magneto-optical properties are studied.