Atomic emission spectral analysis of high-Tc superconducting films and small samples

Methods of determining the stoichiometric composition of the basic components of films and single crystals based on Y-Ba-Cu-O and Bi-Sr-Ca-Cu-O are proposed. The study has been carried out by means of the atomic emission spectral analysis. The spectra were excited in the arc and the emission was recorded by a spectrograph after the sample was dissolved in the diluted nitric acid with the subsequent evaporation of the solution from a graphite powder. We used specially prepared mixtures as reference samples. These mixtures were obtained by depositing standard solutions of the test elements on the graphite powder. The lower limits of the determined masses of the elements were 0.5 μg for Y and Ba, 1.2 μg for Cu, and 2 μg for Bi, Sr, and Ca. The minimum sample masses were 2 μg for the Y compound and 5--8 μg for the Bi compound, respectively. The error in determining the masses was no worse than 15%