Vortex magnetization state in a GMR spin-valve type field sensor

Summary form only given. In this paper, we present a different approach by using circularly shaped elements exhibiting a different magnetization state. The magnetic vortex is one of the fundamental magnetization ground states occurring in disk-shaped thin film elements and is characterized by minimization of the demagnetizing energy at the expense of exchange energy. The state is described as free of hysteresis and planar stray-fields, and discussed as potential oscillator in spin-torque systems, memory bits and magnetic field sensors. In order to compare important parameters like resistance, magnetoresistance amplitude, sensitivity, hysteresis, critical fields like nucleation and annihilation fields in dependence on the free layer thickness and disk radius, single and arrays (10 and 1750 in number) of GMR disks have been fabricated by optical lithography and contacted.