Growth and physical properties of strontium ruthenate films

We have grown single orientation thin films of SrRuO 3 on SrTiO3 by electron beam evaporation with excellent crystallinity and conductivity. Measurements find residual resistivity ratios as high as 90, an order of magnitude higher than previous results, and x-ray diffraction rocking curve widths as low as 0.024°, only slightly larger than the SrTiO 3 rocking curve width of 0.020°. RHEED, AFM, and x-ray diffraction measurements indicate an atomically smooth film surface. We have used these films to study anomalous electron transport and magnetic domain wall physics.; The temperature dependence of resistivity in suggests a crossover from coherent Fermi liquid behavior at temperatures below 25 K, where rho( T) = rho0 + AT2, to incoherent behavior at higher temperatures, where rho(T) = CT0.58. We have studied this crossover through a variety of measurements. Fermi liquid behavior is confirmed at low temperature by the observation of Shubnikov-de Haas oscillations. Infrared reflectivity and time domain terahertz spectroscopy measurements indicate for temperatures from 40 K to 250 K an incoherent regime where sigma1(o) ∝ 1/ w . A low temperature Fermi liquid regime and a high temperature incoherent regime are also seen in electron irradiation studies; below 25 K, the effect of irradiation is consistent with Matthiessen's rule, while above 25 K a negative deviation is seen consistent with incoherent transport.; We have employed SrRuO3 as a model system for studying magnetic domains, a role to which it is well suited due to its strong magnetocrystalline anisotropy. We observe the temperature dependence of the domain wall resistivity and find that the interface resistance of each domain wall is ∼10 -15 O m2. Measurements of the temperature and field dependence of the nucleation of magnetization reversal in SrRuO 3 nanowires fabricated by electron beam lithography are consistent with the presence of a single nucleation energy barrier. The activated volume corresponding to the energy barrier is only (6 nm)3, indicating that nucleation takes place in a small volume and then propagates across the SrRuO3 nanowire. We also observe discrete jumps in the resistance of the SrRuO 3 nanowire versus applied field which we attribute to the creation or annihilation of a single magnetic domain wall.