Influence of nature of the substrate on the soft magnetic properties of pulsed laser ablated-deposited amorphous Co

Abstract Amorphous Co films, ≈270 nm thick, were prepared by pulsed laser ablation-deposition. Substrates of glass, monocrystalline Si(1 1 1), copper and tungsten were used. The surface morphology of the films, studied by means of scanning tunneling microscopy, STM, as well as the coercive field, H c , and room temperature spontaneous magnetization, M s , was determined. The M s values were approximately the same for all films independent of the substrate; on the contrary, significant variation of H c was found for the films grown on different substrates. The lowest coercive field, H c ≈1.2 Oe, corresponds to the samples grown on glass and H c ≈1.6 Oe to the films deposited over Si(1 1 1) substrates, whereas H c ≈2.2 and 5 Oe were measured for the samples deposited over tungsten and copper substrates, respectively. The STM studies allowed us to correlate the different magnetic softness of the films—from both magneto-optical transverse Kerr effect and vibrating sample magnetometry—with their surface morphology.