X-ray photoemission, calorimetric, and electrical transport properties of CeCu4MnyAl1−y

• Ce 4f states well localized in the CeCu4MnyAl1−y compounds.
• Spin-glass contribution to specific heat has been estimated.
• Magnetic phase diagram corroborated for CeCu4MnyAl1−y.
• Lack of a long-range magnetic order in CeCu4Mn confirmed by neutron diffraction.

We report the X-ray photoemission spectra (XPS) and the electrical resistivity measurements for the transition Kondo lattice – spin-glass (SG) in the series CeCu4MnyAl1−y. The study includes additionally the low temperature (down to T = 400 mK) heat capacity results. The XPS measurements revealed that the Ce 4f states are well localized. Electrical resistivity studies illustrate a smooth evolution from the ∼ −ln T relation to the metallic behaviour with the increase of the Mn content. Moreover, the specific heat has been analysed considering the electronic, phonon, Schottky (Crystal Electric Field – CEF), Kondo, and SG contributions. The assumption that the CEF splitting of the energy levels is similar for all the compositions allowed us to estimate the SG and Kondo contribution to the heat capacity. Additionally, the neutron diffraction experiment on the parent CeCu4Mn compound has confirmed that it does not show a long-range magnetic order.