B. Staliński

Hydrogen absorption properties of selected uranium intermetallic compounds

Abstract Some results of an investigation of hydrogen absorption by selected intermetallic compounds of uranium and thorium with nickel, cobalt, manganese and palladium are reported. Of the compounds under consideration, ThNiAl and UNiAl revealed the greatest capability for hydrogen absorption. The basic thermodynamic functions were calculated for hydrides of both these compounds and the lattice constants were determined by an X-ray method.

Single crystal growth of (rare earth)Me3 compounds where Me ≡ Sn, In and Pb

Abstract Single crystals of (La, Ce, Pr, Nd, Sm, Eu, Gd)Sn 3 , (La, Ce, Pr, Nd, Sm, Gd, Yb, Tm)In 3 and EuPb 3 have been grown from slowly cooled solutions of rare earth metals in Sn, In, and Pb metals, respectively. The cooling rate influenced both the crystal size and the morphology of growth.

Low temperature specific heat of f.c.c. ytterbium hydrides

Abstract The results of low temperature specific heat measurements of ytterbium trihydrides YbH2.25, YbH2.37 and YbH2.41 are presented. Flat maxima of Cp(T) are observed at 3.9 K. The magnetic contribution to the specific heat is analysed in terms of Kondo and crystal field effects. Analysis of the heat capacity leads to the conclusion that f.c.c. ytterbium hydrides are heavy-formion systems with an S = 1 2 Kondo model ground state.

Magnetic properties and electron paramagnetic resonance studies of the GdXAlHx (X ≡ Fe, Ni) hydrides

Abstract The pseudobinary compounds GdFeAl and GdNiAl absorb about three and two hydrogen atoms per formula unit respectively. The hydrogen absorption results in an increase in the unit cell volume of GdFeAl and the formation of an unidentified structure with GdNiAl. Detailed magnetization studies of the hydrides have been carried out in the temperature range 4.2–300 K. It follows from these measurements that the absorption of hydrogen leads to a disappearance of the ordering of the iron sublattice in GdFeAl. The magnetization of GdNiAl at 4.2 K shows no tendency to saturate even in fields of up to 140 kOe. This suggests a possible fanning of the rare earth moments in the hydride owing to the weakening of the Gd-Gd exchange interactions. It has been found that anomalies in the electron paramagnetic resonance spectra, i.e . the temperature dependence of the g shift and the linewidth, can be explained by the magnetic properties of the hydrides.

Valence state of ytterbium in non-stoichiometric ytterbium trihydride: A 1H nuclear magnetic resonance and magnetic susceptibility study

Abstract We report the results of a study of ytterbium trihydride performed using continuous wave (wide line) nuclear magnetic resonance (NMR) and magnetic susceptibility measurements. The NMR spectra of YbH3−x (x ≈ 0.45) were obtained at resonance frequencies in the range 6.4–35 MHz and temperatures of 78–295 K. The magnetic susceptibility was measured in the temperature range 4.2–260 K. Both the linewidth and the second moment were found to be field and temperature dependent. The second moments at 78 and 295 K were almost the same, indicating that there was no proton self-diffusion. The calculated second moments for the random distribution of hydrogen in the f.c.c. metal matrix and one model of an ordered hydrogen sublattice are in good agreement with the experimental data. The molar magnetic susceptibility in the temperature range 67–260 K obeys the Curie-Weiss law with μeff = 3.16 μB and θ = −57 K. The magnetic properties of YbH3−x indicate that ytterbium may have two valencies, Yb3+ and Yb2+, in this compound.