Nanofabrication of spin-transfer torque devices by a PMMA mask one step   process: GMR versus single layer devices
  We present a method to prepare magnetic spin torque devices of low specific resistance in a one step lithography process. The quality of the pillar devices is demonstrated for a standard magnetic double layer device. For single layer devices, we found hysteretic switching and a more complex dynamical excitation pattern in higher fields. A simple model to explain the resistance spikes is presented. 
Anne Parge, Tore Niermann, Michael Seibt and Markus M\"unzenberg