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(a) X-ray diffraction scans through the film’s pseudocubic 002 reflection and the substrate peak for the case of films grown at two different temperatures. The sample grown at shows the appearance of a broad film diffraction peak, defining for this sample. At , a clear separation into the and components is apparent (peak splitting); therefore . (b) Crystallization temperature as a function of the -site atomic number for the entire series of scandates. Arrows indicate either a crystallization onset temperature above or no formation of the perovskite phase.
Dielectric constant at of films deposited at different temperatures (circles, left-hand scale) and their refractive index at . Open and solid circles refer to relative permittivities determined from background substrate measurements made before and after the films are measured, respectively, as described in the text. These are placed in the figure to demonstrate the reproducibility of the measurements.
Dielectric constant at (right-hand scale) for the series of rare-earth scandates determined by microwave microscopy with the error bars representing the standard deviation of three measurements for each sample. For comparison, bulk dielectric constants (Ref. 3) (measured at ) are shown as solid circles (multiple data points indicate the tensor coefficients along the principal axes for single-crystal measurements).
Properties of films on , compared to published values. (bulk) is calculated from the unit cell volume (Ref. 14 and 21). The tolerance factor is calculated according to the text. , , , , and refer to the crystallization temperature, thickness, dielectric constant at , refractive index, and direct optical band gap for the thin film samples. For the bulk dielectric constant , all three tensor elements are given where available (measured at ), and bulk values correspond to high absorption band edges. Error bars for are given in parentheses, and brackets indicate references. n/d indicates that no perovskite phase was detected by x-ray diffraction.
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