Standing waves of magnetic edge states in mesoscopic magnetic rings

We have measured the longitudinal and bend magnetoresistance of two-dimensional electron gases modulated by ferromagnetic lateral surface dots and anti-dots, in the presence of a perpendicular magnetic field. We report the observation of oscillations periodic with the magnetic field that become more pronounced at high electron densities. Their period increases with increasing electron density in the case of anti-dots, whereas it decreases with increasing density in the case of dots. A preliminary model, which is based on the quantisation condition of the number of electron orbits around the dot/anti-dot, accounts well for the observed B-periodicity of the oscillations.