Extended Fine Structure in X-Ray Absorption Spectra of Certain Perovskites

Abstract

In this paper we attempt to test the validity of the short-range-order (SRO) and the long-range-order (LRO) theories of the extended fine structure (EFS) in x-ray absorption spectra. This is done by comparing the EFS's of Ti, Ca, Zr, and Sr in the perovoskitelike compounds SrTi${\mathrm{O}}_{3}$, CaTi${\mathrm{O}}_{3}$, SrZr${\mathrm{O}}_{3}$, and CaZr${\mathrm{O}}_{3}$. The regularities which have been anticipated from SRO or LRO theories have not been observed. We are thus led to suggest that models are required other than those which have been used to explain the EFS.