Coercive-force measurements in plated wire

Coercive force values for plated wire as detetermined on a conventional hysteresis looper are discussed. In particular, the variation of Hcwith easy-axis drive amplitude as well as the lack of agreement between the looper Hcand the easy-axis disturb threshold for a discrete bit written into the plated wire is investigated. It has been confirmed that the Hcvariation is a rise-time, not a drive amplitude, effect. In addition, the disagreement between the discrete bit digit-disturb threshold and the looper Hcoccurs because the looper cannot measure any value below the nucleation threshold of the plated wire.