Mossbauer study of Y2Co7-xFexB3 compounds

摘要

The magnetic properties of Y2Co7-xFexB3 for 0.5 <= x <= 2 have been investigated using Fe-57 Mossbauer spectroscopy at room temperature. These compounds have the hexagonal Ce2Co7B3 type of structure. From the Mossbauer spectra, the Y2Co7-xFexB3 compounds are paramagnetic for x = 0.5 and ferromagnetic for 1 < x < 2 at room temperature. The Fe atoms substitute for Co atoms at the 2c site preferentially and avoid Co atoms at the 6i(2) site. The Fe-57 hyperfine fields at each site increased for Y2Co7-xFexB3 with increasing Fe content. In Y2Co6FeB3 the Fe moments at the 2c, 6i(I) and 6i(2) sites are 1.33, 0.87 and 0 mu(B), respectively. It is shown that the Fe atom at the 6i2 site has no moment from the Mossbauer study. The weighted average values of the isomer shift decrease for Y2Co7-xFexB3 with increasing Fe content. (c) 2006 Elsevier Ltd. All rights reserved.