Overpotential driven perpendicular magnetization of electrodeposited ultrathin cobalt films

Depending on the overpotential applied during electrodeposition of ultrathi n cobalt films (eta = 0.1-2.2 V), either in-plane or out-of-plane magnetiza tion can be stabilized. The regime of high supersaturation in particular al lows to engineer electrodeposited cobalt films on Au(111) that show perpend icular magnetization (in the thickness range from 2 to 8 atomic layers) exa ctly like their ultrahigh vacuum grown counterparts. The film topography de pends on the overpotential as shown by atomic force microscopy: continuous films are obtained at low overpotential whereas high overpotential leads to the formation of islands. The perpendicular magnetization results from a s ubtle thickness dependent competition between the shape and the interface a nisotropy. (C) 1998 American Institute of Physics. [S0021-8979(98)48111-8].