Thanks for your answer. I read this article and the next articles which Grushko et al. presented. But, there was not the PDF number of the zeta phase in these articles.
Well, if you find no entry in this database, there is none. But if you work with X-ray diffraction you should be able to handle your problem based on the original articles. In any caseit is always recommended to use such databases only for crude evaluation of data. But to do real science based on your diffraction, please rely on the original literature.