Observation of magnetic switching in submicron magnetic-tunnel junctions at low frequency

Understanding the magnetic switching behavior in micron and submicron scale specimens is important for a number of applications. In this study, magnet ic-tunnel junctions of various sizes and shapes were fabricated and their s witching behavior was studied in detail. Using exchange bias to offset the magnetic response of one electrode, the response of the other (free) electr ode was determined from measurements of junction resistance. Switching thre shold curves were measured by sweeping magnetic fields in both easy and har d direction. Single domain like switching was observed in some of our small est submicron junctions. The observed behavior was compared with prediction s from the Stoner-Wohlfarth rotational model and from numerical calculation s. (C) 1999 American Institute of Physics. [S0021-8979(99)49208-4].