Focused Magneto-optical Kerr Effect measurement of single pseudo spin-valve ring elements

摘要

Micron-scale ferromagnetic ring elements have recently become a subject of interest due to their suitability for use as MRAM elements[1] and magnetic bio-sensors[2]. The majority of work has so far concentrated on single layer ring structures, the properties of which have been well characterised using a variety of experimental techniques[3]. However, in a real magneto-electric device it is likely that either a Giant Magneto-resistive (GMR) or Tunnelling Magneto-resistive multi-layer configuration would be used to increase the available signal, hence, the characterisation of multilayer ring elements is imperative. Currently only electrical resistance measurements[4] and micro-magnetic simulations [5] have been carried out which, while allowing an understanding of the states and switching dynamics of simple pseudo spin-valve (PSV) ring structures, have not permitted a broader study of element geometries.