Structure and composition of iron-containing langmuir-blodgett films

Summary The composition of differently prepared Langmuir-Blodgett multilayers of ferric arachidate has been investigated by means of absorption M?ssbauer spectroscopy and heavy-ion-induced mass spectrometry. We found that the iron concentration in qualitatively good films is 3.5 times higher than the stoichiometric value. Antiferromagnetic ordering in this two-dimensional model substance can be observed when the Fe−Fe distance in the layers is about 0.3 nm or below. The area density of the iron atoms in the planes decreases with decreasingpH values of the subphase which also leads to a disappearance of the long-range magnetic ordering and to a decrease of the Debye temperature of the films which is linearly dependent on the iron concentration in the films. Paper presented at the ICAME-95, Rimini, 10–16 September 1995