Effects of Fe-substitution on the crystal structure and magnetic correlations of the geometrically frustrated antiferromagnets YBaCo4-xFexO7+{delta} (x = 0, 0.2, 0.4, 0.5, 0.6, and 0.8) have been studied by neutron diffraction, Mossbauer spectroscopy, and ac susceptibility. The compounds YBaCo4-xFexO7+{delta} have a special layered-type crystal structure with an alternating Kagome (6c site) and triangular (2a site) layers along the c axis. Fe3+ ions are found to be substituted at both the crystallographic 2a and 6c sites of Co ions. Mossbauer results show a high spin state of Fe3+ ions in a tetrahedral coordination. A reduction in the distortion of the Kagome lattice has been observed with the Fe-substitution. The correlation length of the short-range antiferromagnetic ordering decreases with the Fe-substitution. The sharpness of the magnetic transition also decreases with the Fe-substitution.
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