Energy-scanning X-ray diffraction of synthetic multilayer structure

An energy-scanning X-ray diffraction technique is used to study a synthetic periodic multilayer structure with two amorphous components. The source was the Bremsstrahlung from the X-ray tube, and the detector was a silicon-lithium diode. Experimental results obtained for a multilayer PdSi/MgCu with large period show a deviation from the classical Bragg's law. The deviation is produced by the variation of the refractive index of the multilayer with the wavelength of the incident X-ray. The period d was determined to within 1%. A measure of the refraction index enabled an estimate to be made of the width of each layer. It was also possible to estimate the fluctuation of the period along the multilayer from the full widths of the diffracted Bragg peaks at maximum intensities. The limits of the method are discussed. (orig.)