Low temperature magnetic force microscope study of magnetization reversal in patterned nanoislands of SrRuO3

Abstract

SrRuO 3 is an itinerant ferromagnet (Tc∼150K) characterized by large uniaxial magnetocrystalline anisotropy (K1∼7.7×106erg/cm3) and relatively low saturation magnetization (Ms=213emu/cm3) - properties which make SrRuO3 an extremely hard magnetic material. We have patterned arrays of rectangular nanoislands of a high quality epitaxial film of SrRuO3 with sides ranging between 50 and 500 nm, and studied their magnetization reversal at 4 K using a low temperature magnetic force microscope. We find that the nucleation field for many of the nanoislands is very close to that expected by the Stoner-Wohlfarth model (∼3.8T) and from nanoislands which exhibit partial reversals we can determine an upper bound for the nucleation volume on the order of 100×100×10nm3. We also find that domain wall pinning in the nanoislands is extremely high and in some cases the depinning field exceeds ∼3T.