Growth and magnetism of Co nanometer-scale dots squarely arranged on a Cu(001)-c(2X2)N surface - art. no. 214420

We have studied the growth and magnetism of two-dimensionally coupled nanom eter-scale Co dots which are squarely arranged on a Cu(001)-c(2 x 2)N surfa ce. The morphology was analyzed by scanning tunneling microscopy, and the m agnetization was studied using the magneto-optical Kerr effect. Well-ordere d arrays of two monolayer (ML) thick Co dots interconnected by narrow 1 ML thick Co films can be grown by adjusting the deposited amount of Co. Here w e used selective growth of Co at the clean Cu area of the surface, which co nsists of 5 x 5 nm(2) N-adsorbed c(2 x 2) patches separated by clean Cu lin es of a few nm in width. The observed ferromagnetism in these arrays is con sidered to be mediated by narrow monolayer thick Co films on clean Cu lines . When the average thickness of Co exceeds 1.5 ML, 2 ML thick Co dots are c onnected with each other, and 1 ML Co films grow on the c(2 x 2)N patches. For Co films with an average thickness between 1.8 ML and 2.1 ML, the magne tization is almost constant between 150 K and 370 K, and increases with dec reasing temperature from 150 K. This result suggests that polarization is i nduced in the 1 ML Co film on c(2 x 2)N patches below 150 K.