Evidence for domain condensation near the ferromagnetic to paramagnetic transition in perpendicularly magnetized, ultrathin Fe/2 ML Ni/W[110] films

Ultrathin, fcc Fe/2 ML Ni(111) films were grown on a W(ll0) substrate in UHV by electron beam evaporation. Fe films less than 2.2 ML thick posses a perpendicular moment that does not reorient to an in-plane easy axis below Tc, the temperature of the ferromagnetic to paramagnetic transition. The magnetic susceptibility of the fllms was measured as a function of temperature using the polar Kerr effect. The real part of the susceptibility is …