CALCULATIONS OF THE SENSITIVITY FUNCTION FOR A MIS-ALIGNED THIN-FILM IN A MALLINSON COIL SET

Studies on the accuracy of angular calibrations for VSM measurements o n a thin film sample in the presence of mis-alignments have been perfo rmed by computations of the sensitivity function. The pick-up coils ar e the usual Mallison-type. For a square thin-film sample with dimensio ns of 4 mm x 4 mm, the errors due to displacements or off-center rotat ions of the thin film sample are lower than 5 % for all rotation angle s if the mis-alignments are controlled-to withiin 1 mm. They increase rapidly, however,if the positional mis-alignments are larger than 1 mm . If tile alignment is performed carefully, the errors caused by tilti ng the thin film sample is less than 1 %. Constraints on the edge leng th of the thin film is also useful in preventing excessive errors.