Introduction and control of metastable states in elliptical and rectangular magnetic nanoelements

Small elongated magnetic elements normally support near uniform magnetization distributions and switch abruptly under the influence of fields applied close to their long axes. However metastable states can be introduced in rectangular and elliptical nanoelements by applying fields parallel to their short axes. Using Lorentz microscopy and in situ magnetizing experiments we have established the conditions under which vortex states can be introduced. Their occurrence depends on the formation of a "C" rather than an "S" state as the applied field is reduced following saturation. Micromagnetic modeling provides support for the conclusions drawn from the experimental observations. (C) 2004 American Institute of Physics.