We have elaborated by MBE, Ho/Zr multilayers in which holmium crystall
ographic parameters are considerably reduced compared to bulk. We corr
elate magnetoresistance measurements with the magnetization under very
high magnetic field. We point out a sharp magnetic transition due to
the closing of the conical or helical configurations as in bulk materi
al. This effect disappears for the lower thicknesses of Ho layers and
the transition field changes with the magnetic coupling through the zi
rconium layers.