59Co NMR observation of monolayer resolved hyperfine fields in ultrathin epitaxial FCT-Co(0Â 0Â 1) films

59Co nuclear magnetic resonance measurements have been performed on thin epitaxial FCT-Co(0 0 1) films and the effect of an interface on the Co hyperfine field has been measured with monolayer resolution. Four different sub-lines could be measured within the bulk resonance line and were attributed to Co atoms at various distances from the interface. This effect is observable because of the virtually perfect structural quality of the Co layer, which reduces the width of the resonance lines. In less perfect systems the line width obliterates the effect.