Mössbauer study of Y 2Co7−xFexB3 compounds

The magnetic properties of Y 2Co7−xFexB3 for 0.5 ≤ x ≤ 2 have been investigated using 57Fe Mössbauer spectroscopy at room temperature. These compounds have the hexagonal Ce2Co7B3 type of structure. From the Mössbauer spectra, the Y 2Co7−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 6i2 site. The 57Fe hyperfine fields at each site increased for Y 2Co7−xFexB3 with increasing Fe content. In Y 2Co6FeB3 the Fe moments at the 2c, 6i1 and 6i2 sites are 1.33, 0.87 and 0 μB, respectively. It is shown that the Fe atom at the 6i2 site has no moment from the Mössbauer study. The weighted average values of the isomer shift decrease for Y 2Co7−xFexB3 with increasing Fe content.