X-ray photoelectron spectroscopy and magnetic properties of CeCo7Mn5 and CeCo8Mn4 isostructural ThMn12 type compounds

• The magnetic state of Ce, Co and Mn ions in CeCo7Mn5 and CeCo8Mn4 are analysed.
• XPS has shown the intermediate valence state of Ce.
• Local magnetic moments on both Mn and Co sites were evidenced.
• The magnetic measurements reveal a complex ferromagnetic + antiferromagnetic configuration.

The magnetic properties of CeCo7Mn5 and CeCo8Mn4 compounds have been investigated by combining X-ray photoelectron spectroscopy (XPS) and magnetic measurements in a wide temperature range (4–550) K and magnetic field up to 12 T. X-ray powder diffraction (XRD) measurements showed that CeCo7Mn5 and CeCo8Mn4 compounds are isostructural and crystallize in the ThMn12 structure type. XPS spectra pointed out the intermediate valence state of Ce atoms and that both Co and Mn atoms carry magnetic moments. The complex magnetic structure of CeCo7Mn5 and CeCo8Mn4 is determined by the competition between the ferromagnetic (Co–Co pairs) and antiferromagnetic (Co–Mn and Mn–Mn pairs) interactions. Two different ordering temperatures TN and TC correlated to antiferromagnetic and ferromagnetic coupling of 3d magnetic moments, respectively, are evidenced. Magnetic moments of about 1.6 μB/Co and 3.2 μB/Mn atoms were determined by correlating the magnetic data of the two compounds, in good agreement with the exchange splitting of XPS Co 3s and Mn 3s core levels.