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XPS study of RNiSb2 (R = Pr, Nd) compounds

Szytuła A., Penc B., Jezierski A.

Materials Science Poland

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2008

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Vol. 26, No. 3

759--765

EN

The electronic structure of the ternary RNiSb2 (R = Pr, Nd) compounds, which crystallize in the tetragonal primitive ZrCuSi2-type structure, was studied by the X-ray photoemission spectroscopy. The R3d core-levels and the valence bands were investigated. The results for the PrNiSb2 valence band are compared with the previously calculated density of states. The obtained results indicate that the valence bands are mainly determined by the Ni3d band. The analysis of the XPS spectra of R3d5/2 and R3d3/2 based on the Gunnarsson–Schönhammer model gives the hybridization of the 4f orbitals with the conduction band. The experimental data concerning the valence band of these compounds are compared with the calculations based on the KKR-CPA method. The calculated data for the room temperature (paramagnetic region) give the peaks corresponding to the R4f states at the Fermi level EF = 0. A different distribution of the peaks corresponding to the Ni3d states is observed. For PrNiSb2 three peaks at 2.0, 2.3 and 3.5 eV are observed while for NdNiSb2 a broad maximum between 5.0 and 8.0 eV is visible. The experimental data for PrNiSb2 are in good agreement with the calculated ones while those for NdNiSb2 are not.

2

Electronic structures of RCuIn and R2CuIn3 (R = La, Ce, Pr)

Szytuła A, Kalychak Y M, Tyvanchuk Y, Penc B, Winiarski A

Materials Science Poland

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2008

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Vol. 26, No. 4

1061--1067

EN

Electronic structures of ternary compounds RCuIn and R2CuIn3 (R = La, Ce, Pr) have been studied by the X-ray photoelectron spectroscopy. The valence bands and the XPS core levels were investigated. The two families of compounds crystallize in different hexagonal crystal structures: ZrNiAl-type for RCuIn and AlB2-type for R2CuIn3. Analysis of the XPS valence bands indicates that they are mainly determined by the Cu 3d band. The analysis of the Ce 3d spectra based on the Gunnarsson-Schönhammer model gives the hybridization of the 4f electrons with the conduction band equal to 45 meV for CeCuIn and to 140 meV for Ce2CuIn3. The appearance of the 3d94f0 component is a clear evidence of the intermediate valence behaviour for cerium. The 4f occupation number is 0.95 for CeCuIn and 0.92 for Ce2CuIn3. The analysis of the other core levels confirms a small influence of the atomic surrounding on the electronic structure.

3

Electronic properties of LaNiIn doped with hydrogen

Wasylkowicz Ł., Jezierski A., Szytuła A., Penc B.

Materials Science Poland

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2007

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Vol. 25, No. 4

1229--1234

EN

Electronic properties of RNiInH (R = La,Ce,Nd) intermetallic hydrides were recently studied both experimentally and theoretically. In the present work, we study the influence of hydrogen on the electronic structure of LaNiIn. The electronic structure is calculated by Augmented Spin Wave (ASW) and Tight Binding Linear Muffin Tin Orbital methods within the spin density approximation. The doped hydrogen atoms modify the band structure near the Fermi level. The density of states at the Fermi level decreases with increasing hydrogen concentration but the compounds have metallic character.

4

Electronic structure of the intermetallic rare earth compounds

Szytuła A., Gomółka D., Jezierski A., Penc B., Wawrzyńska E., Winiarski A.

Materials Science Poland

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2006

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Vol. 24, No. 3

557--561

EN

The electronic structures of intermetallic rare earth compounds of different compositions: RMn2Ge2 (R = Nd, Sm), R3Mn4Sn4 (R = La, Ce, Nd), Ce3Ag4X4 (X = Ge, Sn), and Ce2MnGe6, have been investigated. XPS measurements were performed using a commercial LHS10 spectrometer. The valence band and core-level states have been analysed. In Mn compounds, the Mn 3d state forms a broad band near the Fermi level. The analysis of XPS spectra using the Gunnarsson-Schönhammer model gives the coupling parameters (hybridisation energy) between the R 4f states and electrons of the conduction band

5

Magnetic properties and magnetic structure of CeLiGe2 compound

Dmytriv G. S., Pavlyuk V. V., Szytuła A., Penc B., Stusser M., Zygmunt A.

Prace Naukowe. Chemia / Wyższa Szkoła Pedagogiczna w Częstochowie

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2003

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Vol. 8

17--22

EN

X-ray and neutron diffraction as well as magnetic measurements have been performed on CeLiGe2 compound. This compound crystallizes in the orthorhombic CaLiSi2 structure type (Pnma space group). Crystal structure parameters have been refined on the basis of the X-ray data at 293 K and neutron diffraction data at 20 and 1.5 K. Below Tc=9.8(2) K Ce-magnetic moment equal 2.32(6) μB and form ferromagnetic structure with the moments parallel to the b-axis.