Spin switching in mesoscopic ring magnets

In this article a comprehensive investigation of the spin switching in ferromagnetic NiFe and Co ring magnets is reported. Three types of switching (single, double, triple) are identified and the switching type is determined systematically as a function of the geometrical parameters in a phase diagram. The switching types and the switching field variation with varying ring diameter, ring width and film thickness are studied and explained in terms of the different physical processes occurring during the transitions (domain wall depinning, propagation, nucleation, etc.). By adjusting the ring geometry, the switching fields can be tailored over a wide range of values spanning more than an order of magnitude.