Dynamical measurement of domain-wall nucleation and annihilation in individual amorphous Co particles

Abstract

We present magnetization measurements of individual amorphous Co particles (300 nm×200 nm×30 nm) patterned by electron-beam lithography. The hysteresis loops show mainly two magnetization jumps corresponding to domain-wall nucleation and annihilation. The angular dependence of these magnetization jumps is measured and the temperature dependence (0.1-6 K) of the nucleation and the annihilation processes is investigated by two independent methods: switching field and switching time measurements. Finally we compare the results obtained on one particle with those of an array of about 2×(Formula presented) particles. We show experimentally that the dynamical properties measured on individual particles are connected with an unusual 1/T relaxation of the array of particles. © 1996 The American Physical Society.