Structural, Magnetic, and Electronic Properties of CaBaCo4–xMxO7 (M = Fe, Zn)

The effect of substituting iron and zinc for cobalt in CaBaCo4O7 was investigated using neutron diffraction and X-ray absorption spectroscopy techniques. The orthorhombic distortion present in the parent compound CaBaCo4O7 decreases with increasing the content of either Fe or Zn. The samples CaBaCo3ZnO7 and CaBaCo4–xFexO7 with x ≥ 1.5 are metrically hexagonal, but much better refinements in the neutron diffraction patterns are obtained using an orthorhombic unit cell. The two types of substitution have opposite effects on the structural and magnetic properties. Fe atoms preferentially occupy the sites at the triangular layer. Thus, the replacement of Co by Fe suppresses the ferrimagnetic ordering of the parent compound, and CaBaCo4–xFexO7 (0.5 ≤ x ≤ 2) samples are antiferromagnetically ordered following a new propagation vector k = (1/3,0,0). However, the Zn atoms prefer occupying the Kagome layer, which is very detrimental for the long-range magnetic interactions giving rise to a magnetic glass-like beha...