Effect of growth parameters on the structure and magnetic properties of thin polycrystalline Fe films fabricated on Si〈1 0 0〉 substrates

This paper deals with the experimental investigation of the structure and magnetic properties of thin polycrystalline Fe films. Two sets of 50 ± 2 nm thick Fe films were fabricated on Si〈1 0 0〉 substrates with native oxides in place by varying (i) the sputter pressure pAr and (ii) the Fe sputter power PFe. X-ray diffraction (XRD) study revealed that all films grew with strong 〈1 1 0〉 texture normal to the film plane. No higher order peaks were observed in any of the films studied. For both film sets, the lattice constant (a) was less than the bulk Fe lattice constant (a0 = 2.866 Å), which suggested the existence of compressive strain in all films. Two regions of homogeneous strain were observed over the range of pAr studied. Magneto-optical Kerr effect (MOKE) measurements showed that all films exhibited magnetically isotropic behaviour. The magnetic properties were observed to be influenced strongly by pAr. The film grown at pAr = 4 μbar was the most softest (Hs = 100 ± 8 kA m−1, Mr/Ms = 0.87 ± 0.02) film among all the films studied. The magnetic properties were found to be independent of PFe. The effective saturation magnetostriction constant λeff determined (using the Villari method) was positive (4 ± 1 ppm) and observed to vary within the calculated error.