Experimental Confirmation of Field Access Device Modelling

In order to experimentally verify the predictions of a two‐dimensional field access model, two types of experiments have been performed on simple bar patterns. VSM measurements have been used to measure the average magnetization in bar arrays as a function of applied field and field angle relative to the major bar axis, and the results have been found to be in excellent agreement with theory. Effective z‐component fields for several bar patterns have been measured with and without an in‐plane applied field. Comparison with theory is complicated by the presence of an ion‐implanted layer on the surface of the garnet which presumably affects the field of the bubble and, therefore, the outcome of the experiment. Calculations based upon the idealized bubble field give good qualitative and quantitative agreement with experiment, provided an effective spacing is used which takes into account the ion‐implanted layer and consequent reduction in bubble field.