Estudo de propriedades magnéticas de intercalados de oxicloreto de ferro com aminas

Abstract

X-ray diffraction, AC magnetic susceptibility, and Mossbauer spectroscopy were used to characterize the compounds that resul t of intercalation reaction of trietilamine, n-butilamine and benzilamine in the FeOCl matrix. The interlamelar distance, b-direction, has an expressive expansion with intercalation of amines in the van der Waals gaps of the FeOCl. From the results of AC magnetic susceptibility was determined that the magnetic transition in FeOCl and FeOCl(n-butil) is para- to antiferromagnetic, and para- to ferromagnetic in the FeOCl(trietil) compound. Mossbauer spectroscopy has established that all samples shown texture effect, and are Fe3+ spin-up in octahedral symmetry. The observed changes in Mossbauer hyperfine parameters are in according wi th charge transfer from intercalate amine to host matrix layer. The magnetic structure of FeOCl is changed wi th the amine intercalation between i ts layers. The magnetic hyperfine field values of the new sites of iron from intercalate compounds are !arger than correspondent magnetic field in host matrix. These resul ts emphasize the covalence character of the chemical bonds, and reinforce the argument that occur the charge transfer to host matrix. The EFG signal depend of the intercalate amine This signal is negative in FeOCl(n-butil) and FeOCl(benzil) compounds as well as host matrix of FeOCl, and it is positive in FeOCl(trietil).