GMR effect in a single trilayer wire with submicron width

Magnetization reversal phenomena in a submicron magnetic wire with a trilay er structure were investigated by measuring the electric resistance in exte rnal magnetic fields. The critical held for domain wall nucleation was obse rved to be slightly different for each field sweep. The magnetoresistance m easurements were repeated 200 times with a sweep race of 6 Oe/s. The obtain ed distribution of critical fields had two peaks and both moved to higher f ields as temperature was decreased. This result suggests that domain wall n ucleation occurs through a thermally activated process down to 5 K. (C) 199 9 Elsevier Science B.V. All rights reserved.