Electronic structure and transport properties of CeNi9In2

We investigated CeNi9In2 compound, which has been considered as a mixed valence (MV) system. Electrical resistivity vs. temperature variation was analysed in terms of the model proposed by Freimuth for systems with unstable 4f shell. At low temperature the resistivity dependence is consistent with a Fermi liquid state with a contribution characteristic of electron-phonon interaction. Ultraviolet photoemission spectroscopy (UPS) studies of the valence band did not reveal a Kondo peak down to 14 K. A difference of the spectra obtained with photon energies of low and high photoionization cross sections for Ce 4f electrons indicated that 4f states are located mainly close to the Fermi energy. The peaks related to f_{5/2}^1 and f_{7/2}^1 final states cannot be resolved but form a plateau between -0.3 eV and the Fermi energy. X-ray photoemission spectroscopy (XPS) studies were realized for the cerium 3d level. The analysis of XPS spectra within the Gunnarsson-Sh\"onhammer theory yielded a hybridization parameter of 104 meV and non-integer f level occupation, being close to 3. Calculations of partial densities of states were realized by a full potential local orbital (FPLO) method. They confirm that the valence band is dominated by Ni 3d states and are in general agreement with the experiment except for the behavior of f-electrons.Comment: 10 pages, 5 figure

Influence of Co doping on crystal and magnetic properties of Gd_{2}Cu_{2}In

Physical properties of $Gd_2Cu_{2 - x}Co_{x}In$ (x = 0.1, 0.2, 0.3) samples are investigated. The paper brings results of X-ray diffraction, magnetometric as well as specific heat studies. It was found that only sample with x = 0.1 exhibits desired crystal structure. Other compositions show existence of impurities due to lack of dissolution Co atoms. For $Gd_2Cu_{1.9}Co_{0.1}In$ sample the Curie temperature of 92.5 K was evidenced. Thus, an enhancement of ferromagnetic correlations with comparison to $Gd_2Cu_2In$ sample was evidenced. It was found that $Gd_2Cu_{1.9}Co_{0.1}In$ sample exhibits magnetocaloric effect within broad temperature range

Magnetic Properties of Ho5Ni2In4Ho_{5}Ni_{2}In_{4}

X-ray diffraction and magnetic measurements of $Ho_{5}Ni_{2}In_{4}$ are reported. This compound crystallizes in the orthorhombic $Lu_{5}Ni_{2}In_{4}$-type structure. Magnetic data indicate ferromagnetic properties below $T_c$ = 30 K