Perpendicular magnetic domains of a thin Ag/Fe/Ag film observed by magnetic force microscopy at room temperature

Abstract The perpendicular magnetic domains of an ultrathin Fe film on Ag (0 0 1) have been imaged by magnetic force microscopy at room temperature. These films show a thickness-dependent magnetic reorientation transition. They also have a coercive field smaller than 1 mT. Therefore, a very weak magnetic tip has been specially designed for this experiment. Inspite of the weak signal, magnetic domains can be imaged in the regime of perpendicular anisotropy between 3.34 and 3.77 atomic layers film thickness. As expected, the domain size varies strongly with film thickness, with sizes between 580 and 190 nm . The value for K S obtained from the domain size variation agrees well with literature values. Above 3.77 atomic layers of Fe the domains are probably perturbated by the tip and therefore cannot be imaged.