High field magnetoresistance and ESR measurements on Ni stripes on GaAs substrate

Ni nanowires fabricated on a GaAs substrate, which have width narrower than 500 nm and thickness 50 nm, showed an antiferromagnetic-like domain struct ure. Many Ni nanowires fabricated on GaAs using the electron beam lithograp hy technique have been studied by electron spin resonance (ESR). Splitting of ESR signals in the frequency-field diagram was observed around 57GHz, al though only a ferromagnetic resonance mode was observed for other frequenci es. This mode is suggested to be an antiferromagnetic resonance related to the domain structure on the Ni nanowires. (C) 2001 Elsevier Science B.V. Al l rights reserved.