The strain state of epitaxial La0.5Sr0.5MnO3 thin films on BaTiO3 are dynamically tuned by temperature and substrate bias. The resistivity of the La0.5Sr0.5MnO3 thin films is particularly sensitive to changes in structure. Fractional changes in magnetization and resistivity as a function of temperature reveal a direct correlation with fractional changes in the structure, as measured by out-of-plane x-ray diffraction. Fractional changes in resistivity, as large as 30%, are observed for strain induced by the structural phase transitions of the BaTiO3 substrate, and a 12% change is induced by an inverse piezoelectric effect at room temperature.

We grew SrTiO3 on SrTiO3 [001] by pulsed laser deposition, while observing x-ray diffraction at the (00 1 2 ) position. The drop ∆I in the x-ray intensity following a laser pulse contains information about plume-surface interactions. Kinematic theory predicts ∆I I = −4σ(1 − σ), so that ∆I I depends only on the amount of deposited material σ. In contrast, we observed experimentally that | ∆I I | < 4σ(1 − σ), and that ∆I I depends on the phase of x-ray growth oscillations. The combined results suggest a fast smoothing mechanism that depends on surface step-edge density.

Incoherent surface scattering yields a statistical description of the surface, due to the ensemble averaging over many independently sampled volumes. Depending on the state of the surface and direction of the scattering vector relative to the surface normal, the height distribution is discrete, continuous, or a combination of the two. We present a treatment for the influence of multimodal surface height distributions on Crystal Truncation Rod scattering. The effects of a multimodal height distribution are especially evident during insitu monitoring of layer-by-layer thin-film growth via Pulsed Laser Deposition. We model the total height distribution as a convolution of discrete and continuous components, resulting in a broadly applicable parameterization of surface roughness which can be applied to other scattering probes, such as electrons and neutrons. Convolution of such distributions could potentially be applied to interface or chemical scattering.Here we find that this analysis describes accurately our experimental studies of 001 SrTiO 3 annealing and homoepitaxial growth.

We grew SrTiO3 on SrTiO3 (001) by pulsed laser deposition, using x-ray scattering to monitor the growth in real time. The time-resolved small angle scattering exhibits a well-defined length scale associated with the spacing between unit cell high surface features. This length scale imposes a discrete spectrum of Fourier components and rate constants upon the diffusion equation solution, evident in multiple exponential relaxation of the "anti-Bragg" diffracted intensity. An Arrhenius analysis of measured rate constants confirms that they originate from a single activation energy.

High quality epitaxial thin-films of EuTiO3 have been grown on the (001) surface of SrTiO3 using pulsed-laser deposition. In situ x-ray reflectivity measurements reveal that the growth is twodimensional and enable real-time monitoring of the film thickness and roughness during growth. The film thickness, surface mosaic, surface roughness, and strain were characterized in detail using ex situ x-ray diffraction. The thickness and composition were confirmed with Rutherford Back-Scattering. The EuTiO3 thin-films grow two-dimensionally, epitaxially, pseudomorphically, with no measurable in-plane lattice mismatch.